This appendix provides information about administering Oracle Database on HP-UX. It contains the following topics:
When an Oracle Database instance starts, it creates memory segments by dividing the shared memory allocated for creating the Oracle System Global Area (SGA) by the value of the HP-UX shmmax kernel parameter. For example, if 64 GB of shared memory is allocated for a single Oracle instance and the value of the shmmax parameter is 1 GB, then Oracle Database creates 64 shared memory segments for that instance.
Performance degradation can occur when an Oracle instance creates multiple shared memory segments. This is because each shared memory segment receives a unique protection key when Oracle Database creates the instance. The number of protection keys available depends on the system architecture as shown in the following table:
| Architecture | Number of Protection Keys |
|---|---|
| PA-RISC | 6 |
| Itanium | 14 |
If the Oracle instance creates more shared memory segments than the number of protection keys, then the HP-UX operating system displays protection key faults.
Oracle recommends that you set the shmmax parameter value to the amount of available physical memory on the system. Doing this ensures that the entire shared memory for a single Oracle instance is assigned to one shared memory segment and the instance requires only one protection key.
To display the list of active shared memory segments on the system, run the following command:
$ ipcs -m
If Oracle Database creates more segments for the instance than the number of protection keys, then increase the value of the shmmax kernel parameter.
|
See Also: Oracle Database Installation Guide for more information about the recommended minimum kernel parameter values |
On HP-UX, most processes use a time-sharing scheduling policy. Time sharing can have detrimental effects on Oracle performance by descheduling an Oracle process during critical operations, for example, when it is holding a latch. HP-UX has a modified scheduling policy, referred to as SCHED_NOAGE, that specifically addresses this issue. Unlike the normal time-sharing policy, a process scheduled using SCHED_NOAGE does not increase or decrease in priority, nor is it preempted.
This feature is suited to online transaction processing environments because online transaction processing environments can cause competition for critical resources. The use of the SCHED_NOAGE policy with Oracle Database can increase performance by 10 percent or more in online transaction processing environments.
The SCHED_NOAGE policy does not provide the same level of performance gains in decision support environments because there is less resource competition. Because each application and server environment is different, you should test and verify that the environment benefits from the SCHED_NOAGE policy. When using SCHED_NOAGE, Oracle recommends that you exercise caution in assigning highest priority to Oracle processes. Assigning highest SCHED_NOAGE priority to Oracle processes can exhaust CPU resources on the system, causing other user processes to stop responding.
To permit Oracle Database to use the SCHED_NOAGE scheduling policy, the OSDBA group (typically, the dba group) must have the RTSCHED and RTPRIO privileges to change the scheduling policy and set the priority level for Oracle processes. To give the dba group these privileges:
Log in as the root user.
Using any text editor, open the /etc/privgroup file, or create it if necessary.
Add or edit the following line, which begins with the name of the OSDBA group, specifying the privileges RTPRIO and RTSCHED that you want to grant to this group every time the system restarts:
dba RTPRIO RTSCHED
Save the file, and quit the text editor.
Enter the following command to grant the privileges to the OSDBA group:
# /usr/sbin/setprivgrp -f /etc/privgroup
Enter the following command to verify that the privileges are set correctly:
# /usr/bin/getprivgrp dba
Add the HPUX_SCHED_NOAGE initialization parameter to the parameter file for each instance, setting the parameter to an integer value to specify process priority levels. The supported range of values is 178 to 255. Lower values represent higher priorities. The default value of HPUX_SCHED_NOAGE initialization parameter is 178 for all Oracle processes. For LMS processes, this can be changed by setting the initialization parameter _os_sched_high_priority. If the parameter _os_sched_high_priority is between 31 and 2, LMS processes run with SCHED_RR at the set priority. If the parameter value is between 178 and 255, the processes run at the set value with SCHED_NOAGE. However, LMS doesl not run at priority level less than the value of HPUX_SCHED_NOAGE.
If the HPUX_SCHED_NOAGE parameter setting is out of range, then Oracle Database automatically sets the parameter to a permissible value and continues with the SCHED_NOAGE policy with the new value. It also generates a message in the alert_sid.log file about the new setting. Whenever the highest priority is assigned to Oracle processes, either by the user or by automatic readjustment, Oracle Database generates a message in the alert_sid.log file warning about the possibility of exhaustion of CPU resources on the system. Oracle recommends that you set the parameter to assign the priority level you want for Oracle processes.
|
See Also: The HP-UX documentation, thertsched(1) man page, and the rtsched(2) man page for more information about priority policies and priority ranges |
With Oracle Database 11g, you can collect run-time statistics always if the dynamic initialization parameter STATISTICS_LEVEL is set to TYPICAL (default) or ALL. This parameter setting implicitly sets the TIMED_STATISTICS initialization parameter to true. Oracle Database on HP-UX systems uses the gethrtime() system library call to calculate elapsed times during the collection of the statistics. The use of this lightweight system library call enables you to collect run-time statistics always while running an Oracle instance, without affecting performance.
This system library call can provide a performance improvement of up to 10 percent over an Oracle release that does not use the gethrtime() system library call when the TIMED_STATISTICS initialization parameter is explicitly set to true. In addition, there is no negative impact on the online transaction processing performance of an Oracle Database while using the gethrtime() system library call to collect run-time statistics always.
The asynchronous Input-Output pseudo-driver on HP-UX enables Oracle Database to perform Input-Output to raw disk partitions using an asynchronous method, resulting in less Input-Output overhead and higher throughput. You can use the asynchronous Input-Output pseudo-driver on both HP-UX servers and workstations.
This section contains the following topics:
To permit Oracle Database to process asynchronous Input-Output operations, the OSDBA group (dba) must have the MLOCK privilege. To give the dba group the MLOCK privilege:
Log in as the root user.
Using any text editor, open the /etc/privgroup file, or create it if necessary.
Add or edit the following line, which begins with the name of the OSDBA group, specifying the privilege MLOCK:
|
Note: You must use only one line to specify the privileges for a particular group in this file. If the file contains a line for thedba group, then add the MLOCK privilege on the same line. |
dba RTPRIO RTSCHED MLOCK
Save the file, and quit the text editor.
Enter the following command to grant the privileges to the OSDBA group:
# /usr/sbin/setprivgrp -f /etc/privgroup
Enter the following command to verify that the privileges are set correctly:
# /usr/bin/getprivgrp dba
To use asynchronous Input-Output on HP-UX, you must use an Automatic Storage Management disk group that uses raw partitions as the storage option for database files.
|
See Also: Oracle Database Installation Guide for more information about configuring Automatic Storage Management and raw logical volumes on HP-UX systems |
Before you can implement asynchronous Input-Output with either storage option, you must use the System Administrator Management utility to configure the asynchronous disk driver into the HP-UX kernel.
|
Note: In Oracle Database 11g Release 1, you did not have to setDISK_ASYNCH_IO paramter to FALSE on a file system. However, starting with Oracle Database 11g Release 2, if database uses file system for storing the database files, then ensure that you set initialization parameter DISK_ASYNCH_IO to FALSE. By default the value of DISK_ASYNCH_IO is TRUE.
The |
To add the asynchronous disk driver and configure the kernel by using the System Administrator Management utility:
Run the following command as the root user:
# sam
Select the Kernel Configuration area.
Select the Drivers area.
Select the asynchronous disk driver (asyncdsk).
Select Actions, and then select Add Driver to Kernel.
Select List, and then select Configurable Parameters.
Select the MAX_ASYNC_PORTS parameter.
Select Action, and then select Modify Configurable Parameter.
Specify a new value for the parameter, using the following guidelines, and then click OK.
The MAX_ASYNC_PORTS parameter is a configurable HP-UX kernel parameter that controls the maximum number of processes that can open the /dev/async file simultaneously.
The system displays an error message when a process tries to open the /dev/async file after the maximum number of processes have opened the file. This error can reduce performance on systems with a large number of shadow processes or many parallel query slaves performing asynchronous Input-Output. This error is not recorded. To avoid this error, estimate the highest likely number of processes that can access the /dev/async file and set the MAX_ASYNC_PORTS parameter to this value.
Select Actions, and then select Process a New Kernel.
Select one of the following options, and then click OK:
Move Kernel Into Place and Shutdown System/Reboot Now
Do Not Move Kernel Into Place: Do Not Shutdown/Reboot Now
If you choose the second option, then the new kernel, vmunix_test, and the system.SAM configuration file used to create it, are both created in the /stand/build directory.
To enable asynchronous Input-Output operations using the HP-UX asynchronous device driver:
Log in as the root user.
If /dev/async does not exist, use the following command to create it:
# /sbin/mknod /dev/async c 101 0x104
By default, the minor number is set to 0. The following table describes the various minor numbers for 8-bit that you can use to create a device file:
Enter the following command to verify that the /dev/async device file exists and has the major number 101:
# ls -l /dev/async
The output of this command should look similar to the following:
crw------- 1 oracle dba 101 0x000000 Oct 28 10:32 /dev/async
If required, give the device file the operating system owner and permissions consistent with those of the Oracle software owner and OSDBA group.
If the Oracle software owner is oracle and the OSDBA group is dba, then run the following commands:
# /usr/bin/chown oracle:dba /dev/async # /usr/bin/chmod 660 /dev/async
To verify asynchronous Input-Output, first verify that the HP-UX asynchronous driver is configured for Oracle Database, then verify that Oracle Database is executing asynchronous Input-Output through the HP-UX device driver:
Verifying That HP-UX Asynchronous Driver is Configured for Oracle Database
Verifying that Oracle Database is Using Asynchronous Input-Output
To verify that the HP-UX asynchronous driver is configured properly for Oracle Database:
Start Oracle Database with a few parallel query slave processes.
Start the GlancePlus/UX utility as follows:
$ gpm
In the main window, click Reports and then click Process List.
In the Process List window, select one parallel query slave process, select Reports, and then select Process Open Files.
The list of files currently opened by the parallel query slave process is displayed.
In the list of open files, check for the /dev/async file or the 101 0x104000 mode.
If either is in the list, then the /dev/async file has been opened by the parallel query slave process, and the HP-UX asynchronous device driver is configured properly to enable Oracle processes to run asynchronous Input-Output. Make a note of the file descriptor number for the /dev/async file.
To verify that Oracle Database is using asynchronous Input-Output through the HP-UX asynchronous device driver:
Attach the HP-UX tusc utility to the same Oracle parallel query slave that you selected in GlancePlus in the preceding procedure.
Run an Input-Output bound query in the environment.
Check the pattern of read and write calls in the tusc output.
You can do this, for example, by entering the following command, where pid is the process ID of a parallel query slave supposed to process asynchronous Input-Output:
$ tusc -p pid > tusc.output
After running the query, press Ctrl+c to disconnect from the process, and then open the tusc.output file.
The following example shows a sample tusc.output file:
( Attached to process 2052: "ora_p000_tpch" [ 64-bit ]) ................... ........................ [2052] read(9, "80\0\001\013 \b\0\0\0\0\0\0\0\0".., 388) .. = 28 [2052] write(9, "\0\0\00e\0\0\0\080\0\001\013à \0".., 48) .. = 48 [2052] read(9, "80\0\001\013¢ 18\0\0\0\0\0\0\0\0".., 388) .. = 28 [2052] write(9, "\0\0\00e\0\0\0\080\0\001\01bd4\0".., 48) .. = 48
If the DISK_ASYNCH_IO initialization parameter is not explicitly set to false (set to true by default), then the tusc.output file shows a pattern of asynchronous read/write calls of the same file descriptor (9 in the preceding example) back to back.
Map the file descriptor number in the tusc.output file to that used by /dev/async file in GlancePlus. They should match for the particular parallel query slave process. This verifies that Input-Output through the HP-UX asynchronous driver is asynchronous. With synchronous Input-Output, or if the DISK_ASYNCH_IO initialization parameter is explicitly set to FALSE, you do not see the asynchronous read/write pattern described previously. Instead, you see calls to lseek or pread/pwrite. You also see many different file descriptors (the first argument to read/write) instead of just a single file descriptor.
Oracle Database on HP-UX uses a nonblocking polling facility provided by the HP-UX asynchronous driver to check the status of Input-Output operations. This polling is performed by checking a flag that is updated by the asynchronous driver based on the status of the Input-Output operations submitted. HP-UX requires that this flag be in shared memory.
Oracle Database configures an asynchronous flag in the SGA for each Oracle process. Oracle Database on HP-UX has a true asynchronous Input-Output mechanism where Input-Output requests can be issued even though some previously issued Input-Output operations are not complete. This helps to enhance performance and ensures good scalability of parallel Input-Output processes.
Releases of Oracle Database earlier than release 8.1.7 were able to run Input-Output operations only from shared memory by using the HP-UX asynchronous driver. Oracle Database 11g runs Input-Output operations from both shared memory and process-private regions using the new HP-UX asynchronous driver. However, Input-Output operations through the asynchronous driver are not asynchronous in nature. This is because Oracle Database must perform a blocking wait to check the status of Input-Output operations submitted to the asynchronous driver. This causes some Oracle processes, such as the database writer process, to essentially process synchronous Input-Output.
Applications running on Oracle Database 11g can use significantly more memory than applications running on earlier releases. This is because Oracle Database 11g changes the default setting for virtual memory data pages from D (4KB) to L (4 GB) on HP-UX systems.
This section contains the following topics:
By default, Oracle Database uses the largest virtual memory page size setting available on HP-UX for allocating process-private memory. It is defined by the value L (largest.) This value is set as one of the LARGE_PAGE_FLAGS options when linking an Oracle executable.
When the virtual memory page size is set to L, HP-UX allocates the available process-private memory to pages of 1 MB, 4 MB, 16 MB and so on, until it reaches the 1 GB limit, or until it reaches the total amount of allocated memory. If you allocate enough memory to the Oracle PGA for the operating system to be able to allocate memory in larger data page size units, then the operating system allocates the maximum page size at once. For example, if you allocate 48 MB for the Oracle PGA, then the system can have either 3 pages each of 16 MB, or a series of pages in unit sizes with the smaller multiples. For example, four 1 MB pages, three 4 MB pages, and two 16 MB pages. If you allocate 64 MB to the PGA, then the operating system allocates one page of 64 MB, as the data page unit size matches the available memory.
In general, large memory pages yield better application performance by reducing the number of virtual memory translation faults that must be handled by the operating system, freeing more CPU resources for the application. Large pages help to reduce the totìæal number of data pages required to allocate the process-private memory. This reduction decreases the chances of translation lookaside buffer misses at the processor level.
However, if applications are constrained in memory and tend to run a very large number of processes, then this drastic page size increase may lead processes to indicate large memory allocations, followed by an Out of memory error message. If this happens, then you must lower the page size to a value between the D (default) size of 4 KB and the L (largest) size of 4 GB.
With the lowest page size setting (4 KB), CPU utilization can be 20 percent higher than that with a larger page size setting. With the highest setting of L, the memory utilization can be 50 percent higher than that with a 4 MB setting. In cases where the system shows memory constraints, Oracle recommends that you set the page size to match the requirements of the particular application, within the constraints of available memory resources.
For example, an application that has problems with the L setting may show reasonable performance with a 4 MB virtual memory page setting.
To address tuning for the increased memory allocation required for persistent private SQL areas and large virtual memory page sizes, Oracle recommends that you decrease the virtual memory data page size for Oracle Database as required. Use the following command to alter the page size setting:
# /usr/bin/chatr +pd newsize $ORACLE_HOME/bin/oracle
In the preceding example, newsize represents the new value of the virtual memory page size.
Display the new setting using the chatr command as follows:
# /usr/bin/chatr $ORACLE_HOME/bin/oracle
A large base page size enables efficient memory management. The default value for base_pagesize is 4 KB. The new feature introduced with HP-UX 11.31 enables to adjust the size of the base page, by invoking kctune (1 M) to change the tunable base_pagesize and then restart the computer.
|
Note: The base page size feature is not supported on HP-UX PA RISC operating system. |
HP-UX 11i supports dynamic run-time reconfiguration of processor sets and dynamic reassignment of workload between processor sets by valid users.
HP-UX Virtual Partitions enable users to configure their systems in multiple logical partitions where each partition is assigned its own set of processors, memory, and Input-Output resources, and can run a separate instance of the HP-UX operating system. HP-UX processor sets integrated with vPars support dynamic processor migration from one virtual partition to another without requiring a restart of any virtual partition. This helps to provide efficient resource partitioning between applications to minimize interference and guarantees necessary resource allocation to each application running on the HP-UX server.
|
See Also: Refer to the "System and Database Changes" section in the Oracle Database Concepts guide for more information on dynamic resource provisioning |
Network Information Service external naming adapter is supported on HP-UX. To configure and use Network Information Service external naming, refer to the "Configuring External Naming Methods" section of Oracle Database Net Services Administrator's Guide.
The system node names and host names have default length limits of 8 and 64 bytes. The system administrator can configure the system to expand both these limits to 255 bytes.
A dynamic kernel tunable parameter expanded_node_host_names, must be turned on to allow larger names to be set.
To turn on the kernel parameter, run the following command:
kctune expanded_node_host_names=1
To turn off the kernel parameter, run the following command:
kctune expanded_node_host_names=0
This section describes new features that are available with Oracle Database 11g Release 2 (11.2).
The following new feature is provided with Oracle Database 11g Release 2 (11.2.0.3)
Starting with Oracle Database 11g Release 2 (11.2.0.3), cryptographic hardware acceleration for TDE also works with Solaris 11 running on SPARC T3, SPARC T4, and Intel Xeon with AES-NI.
The following new feature is provided with Oracle Database 11g Release 2 (11.2.0.2).
Transparent Data Encryption (TDE) can automatically detect whether the database host system includes specialized cryptographic silicon that accelerates the encryption or decryption processing. When detected, TDE uses the specialized silicon for cryptographic processing accelerating the overall cryptographic performance significantly.
In Oracle Database 11g Release 2 (11.2.0.2), cryptographic hardware acceleration for TDE is only available on Intel Xeon with AES-NI, and for Linux x86 and Linux x86-64 on Oracle Linux 5 and Red Hat Enterprise Linux 5.
Administrator's Reference
11g Release 2 (11.2) for Linux and UNIX-Based Operating Systems
E10839-19
May 2012
Oracle Database Administrator's Reference, 11g Release 2 (11.2) for Linux and UNIX-Based Operating Systems
E10839-19
Copyright © 2006, 2012, Oracle and/or its affiliates. All rights reserved.
Primary Author: Â Ashmita Bose, Namrata Bhakthavatsalam, Reema Khosla, Tanaya Bhattacharjee
Contributing Authors: Â Kevin Flood, Pat Huey, Clara Jaeckel, Emily Murphy, Terri Winters, Prakash Jashnani
Contributors: Subhranshu Banerjee, Mark Bauer, Robert Chang, Jonathan Creighton, Sudip Datta, Thirumaleshwara Hasandka, Joel Kallman, George Kotsovolos, Richard Long, Rolly Lv, Padmanabhan Manavazhi, Matthew Mckerley, Krishna Mohan, Rajendra Pingte, Hanlin Qian, Janelle Simmons, Roy Swonger, Douglas Williams, Joseph Therrattil Koonen, Binoy Sukumaran, and Sumanta Chatterjee.
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This appendix provides information related to using Oracle ODBC Driver. It contains the following sections:
On UNIX platforms, Oracle ODBC driver is certified on the following operating systems using Open Source Driver Manager from unixODBC.org:
| Platform | 32-Bit or 64-Bit | UnixODBC DM version |
|---|---|---|
| Linux x86 | 32-bit | 2.2.14 |
| Linux x86-64 | 32-bit, 64-bit | 2.2.14 |
| IBM: Linux on System z | 32-bit, 64-bit | 2.2.14 |
| Oracle Solaris on SPARC | 32-bit, 64-bit | 2.2.14 |
| IBM AIX on POWER Systems | 32-bit, 64-bit | 2.2.12 |
| Oracle Solaris on x86-64 | 64-bit | 2.2.14 |
| HP-UX Itanium | 32-bit, 64-bit | 2.2.14 |
Oracle ODBC Driver does not support the following ODBC 3.0 features:
Interval data types
SQL_C_UBIGINT and SQL_C_SBIGINT C data type identifiers
Shared connections
Shared environments
The SQL_LOGIN_TIMEOUT attribute of SQLSetConnectAttr
The expired password option
Oracle ODBC Driver does not support the SQL functions listed in the following table:
| String Functions | Numeric Functions | Time, Date, and Interval Functions |
|---|---|---|
BIT_LENGTH | ACOS | CURRENT_DATE |
CHAR_LENGTH | ASIN | CURRENT_TIME |
CHARACTER_LENGTH | ATAN | CURRENT_TIMESTAMP |
DIFFERENCE | ATAN2 | EXTRACT |
OCTET_LENGTH | COT | TIMESTAMPDIFF |
POSITION | DEGREES
|
This section discusses the DATE, TIMESTAMP, and floating point data types.
DATE and TIMESTAMP
The semantics of Oracle DATE and TIMESTAMP data types do not correspond exactly with the ODBC data types with the same names. The Oracle DATE data type contains both date and time information. The SQL_DATE data type contains only date information. The Oracle TIMESTAMP data type also contains date and time information, but it has greater precision in fractional seconds. Oracle ODBC Driver reports the data types of both Oracle DATE and TIMESTAMP columns as SQL_TIMESTAMP to prevent information loss. Similarly, Oracle ODBC Driver binds SQL_TIMESTAMP parameters as Oracle TIMESTAMP values.
|
See Also: "DATE and TIMESTAMP Data Types" for information about the DATE and TIMESTAMP data types related to performance and tuning |
Floating Point Data Types
When connected to an Oracle Database 11g Release 2 (11.2) or later, Oracle ODBC Driver maps the Oracle floating point data types BINARY_FLOAT and BINARY_DOUBLE to the ODBC data types SQL_REAL and SQL_DOUBLE, respectively. In earlier releases, SQL_REAL and SQL_DOUBLE mapped to the generic Oracle numeric data type.
Oracle ODBC Driver and Oracle Database impose limitations on data types. The following table describes these limitations:
| Limited Data Type | Description |
|---|---|
| Literals | Oracle Database limits literals in SQL statements to 4000 bytes. |
SQL_LONGVARCHAR and SQL_WLONGVARCHAR | The Oracle limit for SQL_LONGVARCHAR data, where the column type is LONG, is 2,147,483,647 bytes. The Oracle limit for SQL_LONGVARCHAR data, where the column type is CLOB, is 4 gigabytes. The limiting factor is the client workstation memory. |
SQL_LONGVARCHAR and SQL_LONGVARBINARY | Oracle Database permits only a single long data column in each table. The long data types are SQL_LONGVARCHAR (LONG) and SQL_LONGVARBINARY (LONG RAW). Oracle recommends that you use CLOB and BLOB columns instead. There is no restriction on the number of CLOB and BLOB columns in a table. |
The SQLDriverConnect function is one of the functions implemented by Oracle ODBC Driver. The following table describes the keywords that you can include in the connection string argument of the SQLDriverConnect function call:
| Keyword | Meaning | Value |
|---|---|---|
DSN | ODBC data source name | User-supplied name
This is a mandatory keyword. |
DBQ | TNS service name | User-supplied name
This is a mandatory keyword. |
UID | User ID or user name | User-supplied name
This is a mandatory keyword. |
PWD | Password | User-supplied name
Specify This is a mandatory keyword. |
DBA | Database attribute | W implies write access
|
APA | Applications attributes | T implies that thread safety is to be enabled
|
RST | Result sets | T implies that result sets are to be enabled.
|
QTO | Query timeout option | T implies that query timeout is to be enabled.
|
CSR | Close cursor | T implies that close cursor is to be enabled.
|
BAM | Batch autocommit mode | IfAllSuccessful implies commit only if all statements are successful (old behavior).
|
FBS | Fetch buffer size | User-supplied numeric value (specify a value in bytes of 0 or greater).The default is 60,000 bytes. |
FEN | Failover | T implies failover is to be enabled.
|
FRC | Failover retry count | User-supplied numeric value.
The default is 10. |
FDL | Failover delay | User-supplied numeric value.
The default is 10. |
LOB | LOB writes | T implies LOBs are to be enabled.
|
FWC | Force SQL_WCHAR support | T implies Force SQL_WCHAR is to be enabled.
|
EXC | EXEC syntax | T implies EXEC Syntax is to be enabled.
|
XSM | Schema field | Default implies that the default value is to be used.
|
MDI | Set metadata ID default | T implies that the default value of SQL_ATTR_METADATA_ID is SQL_TRUE.
|
DPM | Disable SQLDescribeParam | T implies that SQLDescribeParam is to be disabled.
|
BTD | Bind TIMESTAMP as DATE | T implies that SQL_TIMESTAMP is to be bound as Oracle DATE.
|
NUM | Numeric settings | NLS implies that the Globalization Support numeric settings are to be used (to determine the decimal and group separator). |
Oracle Database waits indefinitely for lock conflicts between transactions to be resolved. However, you can limit the amount of time that Oracle Database waits for locks to be resolved. To do this, set the SQL_ATTR_QUERY_TIMEOUT attribute of the ODBC SQLSetStmtAttr function while calling this function before connecting to the data source.
When you link the program, you must link it with the Driver Manager library, libodbc.so.
The ODBC SQLSpecialColumns function returns information about the columns in a table. When used with Oracle ODBC Driver, it returns information about the Oracle ROWIDs associated with an Oracle table.
ROWIDs may be used in the WHERE clause of an SQL statement. However, the ROWID value must be presented in a parameter marker.
Oracle reference cursors, also known as result sets, enable an application to retrieve data using stored procedures and stored functions. The following information describes how to use reference cursors to enable result sets through ODBC:
You must use the ODBC syntax for calling stored procedures. Native PL/SQL is not supported through ODBC. The following code sample identifies how to call the procedure or function without a package and within a package. The package name in this case is RSET.
Procedure call:
{CALL Example1(?)}
{CALL RSET.Example1(?)}
Function Call:
{? = CALL Example1(?)}
{? = CALL RSET.Example1(?)}
The PL/SQL reference cursor parameters are omitted when calling the procedure. For example, assume procedure Example2 is defined to have four parameters. Parameters 1 and 3 are reference cursor parameters and parameters 2 and 4 are character strings. The call is specified as:
{CALL RSET.Example2("Literal 1", "Literal 2")}
The following sample application shows how to return a result set by using Oracle ODBC Driver:
/*
* Sample Application using Oracle reference cursors through ODBC
*
* Assumptions:
*
* 1) Oracle Sample database is present with data loaded for the EMP table.
*
* 2) Two fields are referenced from the EMP table, ename and mgr.
*
* 3) A data source has been setup to access the sample database.
*
*
* Program Description:
*
* Abstract:
*
* This program demonstrates how to return result sets using
* Oracle stored procedures
*
* Details:
*
* This program:
* Creates an ODBC connection to the database.
* Creates a Packaged Procedure containing two result sets.
* Executes the procedure and retrieves the data from both result sets.
* Displays the data to the user.
* Deletes the package then logs the user out of the database.
*
*
* The following is the actual PL/SQL this code generates to
* create the stored procedures.
*
DROP PACKAGE ODBCRefCur;
CREATE PACKAGE ODBCRefCur AS
TYPE ename_cur IS REF CURSOR;
TYPE mgr_cur IS REF CURSOR;
PROCEDURE EmpCurs(Ename IN OUT ename_cur, Mgr IN OUT mgr_cur, pjob IN VARCHAR2);
END;
/
CREATE PACKAGE BODY ODBCRefCur AS
PROCEDURE EmpCurs(Ename IN OUT ename_cur, Mgr IN OUT mgr_cur, pjob IN VARCHAR2)
AS
BEGIN
IF NOT Ename%ISOPEN
THEN
OPEN Ename for SELECT ename from emp;
END IF;
IF NOT Mgr%ISOPEN
THEN
OPEN Mgr for SELECT mgr from emp where job = pjob;
END IF;
END;
END;
/
*
* End PL/SQL for Reference Cursor.
*/
/*
* Include Files
*/
#include <stdio.h>
#include <sql.h>
#include <sqlext.h>
/*
* Defines
*/
#define JOB_LEN 9
#define DATA_LEN 100
#define SQL_STMT_LEN 500
/*
* Procedures
*/
void DisplayError( SWORD HandleType, SQLHANDLE hHandle, char *Module );
/*
* Main Program
*/
int main()
{
SQLHENV hEnv;
SQLHDBC hDbc;
SQLHSTMT hStmt;
SQLRETURN rc;
char *DefUserName ="jones";
char *DefPassWord ="password";
SQLCHAR ServerName[DATA_LEN];
SQLCHAR *pServerName=ServerName;
SQLCHAR UserName[DATA_LEN];
SQLCHAR *pUserName=UserName;
SQLCHAR PassWord[DATA_LEN];
SQLCHAR *pPassWord=PassWord;
char Data[DATA_LEN];
SQLINTEGER DataLen;
char error[DATA_LEN];
char *charptr;
SQLCHAR SqlStmt[SQL_STMT_LEN];
SQLCHAR *pSqlStmt=SqlStmt;
char *pSalesMan = "SALESMAN";
SQLINTEGER sqlnts=SQL_NTS;
/*
* Allocate the Environment Handle
*/
rc = SQLAllocHandle( SQL_HANDLE_ENV, SQL_NULL_HANDLE, &hEnv );
if (rc != SQL_SUCCESS)
{
printf( "Cannot Allocate Environment Handle\n");
printf( "\nHit Return to Exit\n");
charptr = gets ((char *)error);
exit(1);
}
/*
* Set the ODBC Version
*/
rc = SQLSetEnvAttr( hEnv,SQL_ATTR_ODBC_VERSION,(void *)SQL_OV_ODBC3,0);
if (rc != SQL_SUCCESS)
{
printf( "Cannot Set ODBC Version\n");
printf( "\nHit Return to Exit\n");
charptr = gets ((char *)error);
exit(1);
}
/*
* Allocate the Connection handle
*/
rc = SQLAllocHandle( SQL_HANDLE_DBC, hEnv, &hDbc );
if (rc != SQL_SUCCESS)
{
printf( "Cannot Allocate Connection Handle\n");
printf( "\nHit Return to Exit\n");
charptr = gets ((char *)error);
exit(1);
}
/*
* Get User Information
*/
strcpy ((char *) pUserName, DefUserName );
strcpy ((char *) pPassWord, DefPassWord );
/*
* Data Source name
*/
printf( "\nEnter the ODBC Data Source Name\n" );
charptr = gets ((char *) ServerName);
/*
* User Name
*/
printf ( "\nEnter User Name Default [%s]\n", pUserName);
charptr = gets ((char *) UserName);
if (*charptr == '\0')
{
strcpy ((char *) pUserName, (char *) DefUserName );
}
/*
* Password
*/
printf ( "\nEnter Password Default [%s]\n", pPassWord);
charptr = gets ((char *)PassWord);
if (*charptr == '\0')
{
strcpy ((char *) pPassWord, (char *) DefPassWord );
}
/*
* Connection to the database
*/
rc = SQLConnect( hDbc,pServerName,(SQLSMALLINT) strlen((char *)pServerName),pUserName,(SQLSMALLINT) strlen((char *)pUserName),pPassWord,(SQLSMALLINT) strlen((char *)pPassWord));
if (rc != SQL_SUCCESS)
{
DisplayError(SQL_HANDLE_DBC, hDbc, "SQLConnect");
}
/*
* Allocate a Statement
*/
rc = SQLAllocHandle( SQL_HANDLE_STMT, hDbc, &hStmt );
if (rc != SQL_SUCCESS)
{
printf( "Cannot Allocate Statement Handle\n");
printf( "\nHit Return to Exit\n");
charptr = gets ((char *)error);
exit(1);
}
/*
* Drop the Package
*/
strcpy( (char *) pSqlStmt, "DROP PACKAGE ODBCRefCur");
rc = SQLExecDirect(hStmt, pSqlStmt, strlen((char *)pSqlStmt));
/*
* Create the Package Header
*/
strcpy( (char *) pSqlStmt, "CREATE PACKAGE ODBCRefCur AS\n");
strcat( (char *) pSqlStmt, " TYPE ename_cur IS REF CURSOR;\n");
strcat( (char *) pSqlStmt, " TYPE mgr_cur IS REF CURSOR;\n\n");
strcat( (char *) pSqlStmt, " PROCEDURE EmpCurs (Ename IN OUT ename_cur,");
strcat( (char *) pSqlStmt, "Mgr IN OUT mgr_cur,pjob IN VARCHAR2);\n\n");
strcat( (char *) pSqlStmt, "END;\n");
rc = SQLExecDirect(hStmt, pSqlStmt, strlen((char *)pSqlStmt));
if (rc != SQL_SUCCESS)
{
DisplayError(SQL_HANDLE_STMT, hStmt, "SQLExecDirect");
}
/*
* Create the Package Body
*/
strcpy( (char *) pSqlStmt, "CREATE PACKAGE BODY ODBCRefCur AS\n");
strcat( (char *) pSqlStmt, " PROCEDURE EmpCurs (Ename IN OUT ename_cur,");
strcat( (char *) pSqlStmt, "Mgr IN OUT mgr_cur, pjob IN VARCHAR2)\n AS\n BEGIN\n");
strcat( (char *) pSqlStmt, " IF NOT Ename%ISOPEN\n THEN\n");
strcat( (char *) pSqlStmt, " OPEN Ename for SELECT ename from emp;\n");
strcat( (char *) pSqlStmt, " END IF;\n\n");
strcat( (char *) pSqlStmt, " IF NOT Mgr%ISOPEN\n THEN\n");
strcat( (char *) pSqlStmt, " OPEN Mgr for SELECT mgr from emp where job = pjob;\n");
strcat( (char *) pSqlStmt, " END IF;\n");
strcat( (char *) pSqlStmt, " END;\n");
strcat( (char *) pSqlStmt, "END;\n");
rc = SQLExecDirect(hStmt, pSqlStmt, strlen((char *)pSqlStmt));
if (rc != SQL_SUCCESS)
{
DisplayError(SQL_HANDLE_STMT, hStmt, "SQLExecDirect");
}
/*
* Bind the Parameter
*/
r €ÿc = SQLBindParameter(hStmt,1,SQL_PARAM_INPUT,SQL_C_CHAR,SQL_CHAR,JOB_LEN,0,pSalesMan,0,&sqlnts);
/*
* Call the Store Procedure which executes the Result Sets
*/
strcpy( (char *) pSqlStmt, "{CALL ODBCRefCur.EmpCurs(?)}");
rc = SQLExecDirect(hStmt, pSqlStmt, strlen((char *)pSqlStmt));
if (rc != SQL_SUCCESS)
{
DisplayError(SQL_HANDLE_STMT, hStmt, "SQLExecDirect");
}
/*
* Bind the Data
*/
rc = SQLBindCol( hStmt,1,SQL_C_CHAR,Data,sizeof(Data),&DataLen);
if (rc != SQL_SUCCESS)
{
DisplayError(SQL_HANDLE_STMT, hStmt, "SQLBindCol");
}
/*
* Get the data for Result Set 1
*/
printf( "\nEmployee Names\n\n");
while ( rc == SQL_SUCCESS )
{
rc = SQLFetch( hStmt );
if ( rc == SQL_SUCCESS )
{
printf("%s\n", Data);
}
else
{
if (rc != SQL_NO_DATA)
{
DisplayError(SQL_HANDLE_STMT, hStmt, "SQLFetch");
}
}
}
printf( "\nFirst Result Set - Hit Return to Continue\n");
charptr = gets ((char *)error);
/*
* Get the Next Result Set
*/
rc = SQLMoreResults( hStmt );
if (rc != SQL_SUCCESS)
{
DisplayError(SQL_HANDLE_STMT, hStmt, "SQLMoreResults");
}
/*
* Get the data for Result Set 2
*/
printf( "\nManagers\n\n");
while ( rc == SQL_SUCCESS )
{
rc = SQLFetch( hStmt );
if ( rc == SQL_SUCCESS )
{
printf("%s\n", Data);
}
else
{
if (rc != SQL_NO_DATA)
{
DisplayError(SQL_HANDLE_STMT, hStmt, "SQLFetch");
}
}
}
printf( "\nSecond Result Set - Hit Return to Continue\n");
charptr = gets ((char *)error);
/*
* Should Be No More Results Sets
*/
rc = SQLMoreResults( hStmt );
if (rc != SQL_NO_DATA)
{
DisplayError(SQL_HANDLE_STMT, hStmt, "SQLMoreResults");
}
/*
* Drop the Package
*/
strcpy( (char *) pSqlStmt, "DROP PACKAGE ODBCRefCur");
rc = SQLExecDirect(hStmt, pSqlStmt, strlen((char *)pSqlStmt));
/*
* Free handles close connections to the database
*/
SQLFreeHandle( SQL_HANDLE_STMT, hStmt );
SQLDisconnect( hDbc );
SQLFreeHandle( SQL_HANDLE_DBC, hDbc );
SQLFreeHandle( SQL_HANDLE_ENV, hEnv );
printf( "\nAll Done - Hit Return to Exit\n");
charptr = gets ((char *)error);
return(0);
}
/*
* Display Error Messages
*/
void DisplayError( SWORD HandleType, SQLHANDLE hHandle, char *Module )
{
SQLCHAR MessageText[255];
SQLCHAR SQLState[80];
SQLRETURN rc=SQL_SUCCESS;
long NativeError;
SWORD RetLen;
SQLCHAR error[25];
char *charptr;
rc =
SQLGetDiagRec(HandleType,hHandle,1,SQLState,&NativeError,MessageText,255,&RetLen);
printf( "Failure Calling %s\n", Module );
if (rc == SQL_SUCCESS || rc == SQL_SUCCESS_WITH_INFO)
{
printf( "\t\t\t State: %s\n", SQLState);
printf( "\t\t\t Native Error: %d\n", NativeError );
printf( "\t\t\t Error Message: %s\n", MessageText );
}
printf( "\nHit Return to Exit\n");
charptr = gets ((char *)error);
exit(1);
}
If the syntax of the SQL Server EXEC statement can be readily translated to an equivalent Oracle procedure call without requiring any change to it, then Oracle ODBC Driver can translate it if you enable this option.
The complete name of a SQL Server procedure consists of up to four identifiers:
Server name
Database name
Owner name
Procedure name
The format for the name is:
[[[server.][database].][owner_name].]procedure_name
During the migration of Microsoft SQL Server database to Oracle Database, the definition of each SQL Server procedure or function is converted to its equivalent Oracle Database syntax and is defined in a schema in Oracle Database. Migrated procedures are often reorganized (and created in schemas) in one of the following ways:
All procedures are migrated to one schema (the default option).
All procedures defined in one SQL Server database are migrated to the schema named with that database name.
All procedures owned by one user are migrated to the schema named with that user's name.
To support these three ways of organizing migrated procedures, you can specify one of these schema name options for translating procedure names. Object names in the translated Oracle procedure call are not case-sensitive.
This sections provides information about the functionality supported by Oracle ODBC Driver. It contains the following sections:
Oracle ODBC Driver release 10.2.0.1.0 and higher supports all Core, Level 2, and Level 1 functions.
The following table describes how Oracle ODBC Driver implements specific functions:
| Function | Description |
|---|---|
SQLConnect | SQLConnect requires only a DBQ, user ID, and password. |
SQLDriverConnect | SQLDriverConnect uses the DSN, DBQ, UID, and PWD keywords. |
SQLSpecialColumns | If SQLSpecialColumns is called with the SQL_BEST_ROWID attribute, then it always returns the ROWID column. |
SQLProcedures and SQLProcedureColumns | Refer to the information in the following row. |
| All catalog functions | If the SQL_ATTR_METADATA_ID statement attribute is set to SQL_TRUE, then a string argument is treated as an identifier argument, and its case is not significant. In this case, the underscore (_) and the percent sign (%) are treated as the actual character, and not as a search pattern character. In contrast, if this attribute is set to SQL_FALSE, then it is either an ordinary argument or a pattern value argument and is treated literally, and its case is significant. |
SQLProcedures and SQLProcedureColumns
The SQLProcedures and SQLProcedureColumns calls have been modified to locate and return information about all procedures and functions even if they are contained within a package. In earlier releases, the calls only found procedures and functions that were outside of packages. The following examples and scenarios show what procedures or functions are returned if the SQL_ATTR_METADATA_ID attribute is set to SQL_FALSE.
Suppose that you have the following stored procedures:
"BAR" "BARX" "XBAR" "XBARX" "SQLPROCTEST.BAR" "SQLPROCTEST.BARX" "SQLPROCTEST.XBAR" "SQLPROCTEST.XBARX"
When you look for % or %%%%%%, you get all eight procedures.
When you look for %_ or _%, you get the following:
BAR BARX XBAR XBARX
When you look for . or .% or %.% or SQLPROC%. or SQLPROC%.%, you get the following:
SQLPROCTEST.BAR SQLPROCTEST.BARX SQLPROCTEST.XBAR SQLPROCTEST.XBARX
When you look for %BAR, you get the following:
BAR XBAR
When you look for .%BAR or %.%BAR, you get the following:
SQLPROCTEST.BAR SQLPROCTEST.XBAR
When you look for SQLPROC% or .SQLPROC%, you get the following:
nothing (0 rows)
If a comparison predicate has a parameter marker as the second expression in the comparison and the value of that parameter is set to SQL_NULL_DATA with SQLBindParameter, then the comparison fails. This is consistent with the null predicate syntax in ODBC SQL.
For programmers, the most important part of the implementation of the data types concerns the CHAR, VARCHAR, and VARCHAR2 data types.
For an fSqlType value of SQL_VARCHAR, SQLGetTypeInfo returns the Oracle Database data type VARCHAR2. For an fSqlType value of SQL_CHAR, SQLGetTypeInfo returns the Oracle Database data type CHAR.
This section provide information about Unicode support. It contains the following topics:
ODBC Driver Manager makes all ODBC drivers, regardless of whether they support Unicode, appear as if they are Unicode compliant. This allows ODBC applications to be written independent of the Unicode capabilities of underlying ODBC drivers.
The extent to which the Driver Manager can emulate Unicode support for ANSI ODBC drivers is limited by the conversions possible between the Unicode data and the local code page. Data loss is possible when the Driver Manager is converting from Unicode to the local code page. Full Unicode support is not possible unless the underlying ODBC driver supports Unicode. Oracle ODBC Driver provides full Unicode support.
The ODBC API supports both Unicode and ANSI entry points using the W and A suffix convention. An ODBC application developer does not must explicitly call entry points with the suffix. An ODBC application that is compiled with the UNICODE and _UNICODE preprocessor definitions generates the appropriate calls. For example, a call to SQLPrepare compiles as SQLPrepareW.
The C data type, SQL_C_WCHAR, was added to the ODBC interface to allow applications to specify that an input parameter is encoded as Unicode or to request column data returned as Unicode. The macro SQL_C_TCHAR is useful for applications that must be built as both Unicode and ANSI. The SQL_C_TCHAR macro compiles as SQL_C_WCHAR for Unicode applications and as SQL_C_CHAR for ANSI applications.
The SQL data types, SQL_WCHAR, SQL_WVARCHAR, and SQL_WLONGVARCHAR, have been added to the ODBC interface to represent columns defined in a table as Unicode. Potentially, these values are returned from calls to SQLDescribeCol, SQLColAttribute, SQLColumns, and SQLProcedureColumns.
Unicode encoding is supported for SQL column types NCHAR, NVARCHAR2, and NCLOB. In addition, Unicode encoding is also supported for SQL column types CHAR and VARCHAR2 if the character semantics are specified in the column definition.
Oracle ODBC Driver supports these SQL column types and maps them to ODBC SQL data types. The following table lists the supported SQL data types and the equivalent ODBC SQL data type:
| SQL Data Types | ODBC SQL Data Types |
|---|---|
CHAR | SQL_CHAR or SQL_WCHAR |
VARCHAR2 | SQL_VARCHAR or SQL_WVARCHAR |
NCHAR | SQL_WCHAR |
NVARCHAR2 | SQL_WVARCHAR |
NCLOB | SQL_WLONGVARCHAR |
The SQLGetData function allows an ODBC application to specify the data type to receive a column as after the data has been fetched. OCI requires Oracle ODBC Driver to specify the data type before it is fetched. In this case, Oracle ODBC Driver uses information about the data type of the column (as defined in the database) to determine how to best default to fetching the column through OCI.
If a column that contains character data is not bound by SQLBindCol, then Oracle ODBC Driver must determine if it should fetch the column as Unicode or as the local code page. The driver could always default to receiving the column as Unicode. However, this may result in as many as two unnecessary conversions. For example, if the data were encoded in the database as ANSI, then there would be an ANSI to Unicode conversion to fetch the data into Oracle ODBC Driver. If the ODBC application then requested the data as SQL_C_CHAR, then there would be an additional conversion to revert the data to its original encoding.
The default encoding of Oracle Database Client is used when fetching data. However, an ODBC application may overwrite this default and fetch the data as Unicode by binding the column or the parameter as the WCHAR data type.
Because Oracle ODBC Driver itself was implemented using TCHAR macros, it is recommended that ODBC application programs use TCHAR in order to take advantage of the driver.
The following examples show how to use TCHAR, which becomes the WCHAR data type if you compile with UNICODE and _UNICODE:
Example E-1 Connection to Database
To use this code, you only must specify the Unicode literals for SQLConnect.
HENV envHnd;
HDBC conHnd;
HSTMT stmtHnd;
RETCODE rc;
rc = SQL_SUCCESS;
// ENV is allocated
rc = SQLAllocEnv(&envHnd);
// Connection Handle is allocated
rc = SQLAllocConnect(envHnd, &conHnd);
rc = SQLConnect(conHnd, _T("stpc19"), SQL_NTS, _T("jones"), SQL_NTS, _T("password"), SQL_NTS);
.
.
.
if (conHnd)
SQLFreeConnect(conHnd);
if (envHnd)
SQLFreeEnv(envHnd);
Example E-2 Simple Retrieval
The following example retrieves the employee names and the job tiles from the EMP table. With the exception that you must specify TCHAR compliant data to every ODBC function, there is no difference to the ANSI case. If the case is a Unicode application, then you must specify the length of the buffer to the BYTE length when you call SQLBindCol. For example, sizeof(ename).
/*
** Execute SQL, bind columns, and Fetch.
** Procedure:
**
** SQLExecDirect
** SQLBindCol
** SQLFetch
**
*/
static SQLTCHAR *sqlStmt = _T("SELECT ename, job FROM emp");
SQLTCHAR ename[50];
SQLTCHAR job[50];
SQLINTEGER enamelen, joblen;
_tprintf(_T("Retrieve ENAME and JOB using SQLBindCol 1.../n[%s]/n"), sqlStmt);
// Step 1: Prepare and Execute
rc = SQLExecDirect(stmtHnd, sqlStmt, SQL_NTS); // select
checkSQLErr(envHnd, conHnd, stmtHnd, rc);
// Step 2: Bind Columns
rc = SQLBindCol(stmtHnd,
1,
SQL_C_TCHAR,
ename,
sizeof(ename),
&enamelen);
checkSQLErr(envHnd, conHnd, stmtHnd, rc);
rc = SQLBindCol(stmtHnd,
2,
SQL_C_TCHAR,
job,
sizeof(job),
&joblen);
checkSQLErr(envHnd, conHnd, stmtHnd, rc);
do
{
// Step 3: Fetch Data
rc = SQLFetch(stmtHnd);
if (rc == SQL_NO_DATA)
break;
checkSQLErr(envHnd, conHnd, stmtHnd, rc);
_tprintf(_T("ENAME = %s, JOB = %s/n"), ename, job);
} while (1);
_tprintf(_T("Finished Retrieval/n/n"));
Example E-3 Retrieval Using SQLGetData (Binding After Fetch)
This example shows how to use SQLGetData. There is no difference to the ANSI application in terms of Unicode-specific issues.
/*
** Execute SQL, bind columns, and Fetch.
** Procedure:
**
** SQLExecDirect
** SQLFetch
** SQLGetData
*/
static SQLTCHAR *sqlStmt = _T("SELECT ename,job FROM emp"); // same as Case 1.
SQLTCHAR ename[50];
SQLTCHAR job[50];
_tprintf(_T("Retrieve ENAME and JOB using SQLGetData.../n[%s]/n"), sqlStmt);
if (rc != SQL_SUCCESS)
{
_tprintf(_T("Failed to allocate STMT/n"));
goto exit2;
}
// Step 1: Prepare and Execute
rc = SQLExecDirect(stmtHnd, sqlStmt, SQL_NTS); // select
checkSQLErr(envHnd, conHnd, stmtHnd, rc);
do
{
// Step 2: Fetch
rc = SQLFetch(stmtHnd);
if (rc == SQL_NO_DATA)
break;
checkSQLErr(envHnd, conHnd, stmtHnd, rc);
// Step 3: GetData
rc = SQLGetData(stmtHnd,
1,
SQL_C_TCHAR,
(SQLPOINTER)ename,
sizeof(ename),
NULL);
checkSQLErr(envHnd, conHnd, stmtHnd, rc);
rc = SQLGetData(stmtHnd,
2,
SQL_C_TCHAR,
(SQLPOINTER)job,
sizeof(job),
NULL);
checkSQLErr(envHnd, conHnd, stmtHnd, rc);
_tprintf(_T("ENAME = %s, JOB = %s/n"), ename, job);
} while (1);
_tprintf(_T("Finished Retrieval/n/n"));
Example E-4 Simple Update
This example shows how to update data. The length of data for SQLBindParameter has to be specified with the BYTE length, even in Unicode application.
/*
** Execute SQL, bind columns, and Fetch.
** Procedure:
**
** SQLPrepare
** SQLBindParameter
** SQLExecute
*/
static SQLTCHAR *sqlStmt = _T("INSERT INTO emp(empno,ename,job) VALUES(?,?,?)");
static SQLTCHAR *empno = _T("9876"); // Emp No
static SQLTCHAR *ename = _T("ORACLE"); // Name
static SQLTCHAR *job = _T("PRESIDENT"); // Job
_tprintf(_T("Insert User ORACLE using SQLBindParameter.../n[%s]/n"), sqlStmt);
// Step 1: Prepare
rc = SQLPrepare(stmtHnd, sqlStmt, SQL_NTS); // select
checkSQLErr(envHnd, conHnd, stmtHnd, rc);
// Step 2: Bind Parameter
rc = SQLBindParameter(stmtHnd,
1,
SQL_PARAM_INPUT,
SQL_C_TCHAR,
SQL_DECIMAL,
4, // 4 digit
0,
(SQLPOINTER)empno,
0,
NULL);
checkSQLErr(envHnd, conHnd, stmtHnd, rc);
rc = SQLBindParameter(stmtHnd,
2,
SQL_PARAM_INPUT,
SQL_C_TCHAR,
SQL_CHAR,
lstrlen(ename)*sizeof(TCHAR),
0,
(SQLPOINTER)ename,
lstrlen(ename)*sizeof(TCHAR),
NULL);
checkSQLErr(envHnd, conHnd, stmtHnd, rc);
rc = SQLBindParameter(stmtHnd,
3,
SQL_PARAM_INPUT,
SQL_C_TCHAR,
SQL_CHAR,
lstrlen(job)*sizeof(TCHAR),
0,
(SQLPOINTER)job,
lstrlen(job)*sizeof(TCHAR),
NULL);
checkSQLErr(envHnd, conHnd, stmtHnd, rc);
// Step 3: Execute
rc = SQLExecute(stmtHnd);
checkSQLErr(envHnd, conHnd, stmtHnd, rc);
Example E-5 Update and Retrieval for Long Data (CLOB)
This example may be the most complicated case to update and retrieve data for long data, like CLOB, in Oracle Database. Because the length of data should always be the BYTE length, the expression lstrlen(TCHAR data)*sizeof(TCHAR) is needed to derive the BYTE length.
/*
** Execute SQL, bind columns, and Fetch.
** Procedure:
**
** SQLPrepare
** SQLBindParameter
** SQLExecute
** SQLParamData
** SQLPutData
**
** SQLExecDirect
** SQLFetch
** SQLGetData
*/
static SQLTCHAR *sqlStmt1 = _T("INSERT INTO clobtbl(clob1) VALUES(?)");
static SQLTCHAR *sqlStmt2 = _T("SELECT clob1 FROM clobtbl");
SQLTCHAR clobdata[1001];
SQLTCHAR resultdata[1001];
SQLINTEGER ind = SQL_DATA_AT_EXEC;
SQLTCHAR *bufp;
int clobdatalen, chunksize, dtsize, retchklen;
_tprintf(_T("Insert CLOB1 using SQLPutData.../n[%s]/n"), sqlStmt1);
// Set CLOB Data
{
int i;
SQLTCHAR ch;
for (i=0, ch=_T('A'); i< sizeof(clobdata)/sizeof(SQLTCHAR); ++i, ++ch)
{
if (ch > _T('Z'))
ch = _T('A');
clobdata[i] = ch;
}
clobdata[sizeof(clobdata)/sizeof(SQLTCHAR)-1] = _T('/0');
}
clobdatalen = lstrlen(clobdata); // length of characters
chunksize = clobdatalen / 7; // 7 times to put
// Step 1: Prepare
rc = SQLPrepare(stmtHnd, sqlStmt1, SQL_NTS);
checkSQLErr(envHnd, conHnd, stmtHnd, rc);
// Step 2: Bind Parameter with SQL_DATA_AT_EXEC
rc = SQLBindParameter(stmtHnd,
1,
SQL_PARAM_INPUT,
SQL_C_TCHAR,
SQL_LONGVARCHAR,
clobdatalen*sizeof(TCHAR),
0,
(SQLPOINTER)clobdata,
clobdatalen*sizeof(TCHAR),
&ind);
checkSQLErr(envHnd, conHnd, stmtHnd, rc);
// Step 3: Execute
rc = SQLExecute(stmtHnd);
checkSQLErr(envHnd, conHnd, stmtHnd, rc);
// Step 4: ParamData (initiation)
rc = SQLParamData(stmtHnd, (SQLPOINTER*)&bufp); // set value
checkSQLErr(envHnd, conHnd, stmtHnd, rc);
for (dtsize=0, bufp = clobdata;
dtsize < clobdatalen;
dtsize += chunksize, bufp += chunksize)
{
int len;
if (dtsize+chunksize<clobdatalen)
len = chunksize;
else
len = clobdatalen-dtsize;
// Step 5: PutData
rc = SQLPutData(stmtHnd, (SQLPOINTER)bufp, len*sizeof(TCHAR));
checkSQLErr(envHnd, conHnd, stmtHnd, rc);
}
// Step 6: ParamData (temination)
rc = SQLParamData(stmtHnd, (SQLPOINTER*)&bufp);
checkSQLErr(envHnd, conHnd, stmtHnd, rc);
rc = SQLFreeStmt(stmtHnd, SQL_CLOSE);
_tprintf(_T("Finished Update/n/n"));
rc = SQLAllocStmt(conHnd, &stmtHnd);
if (rc != SQL_SUCCESS)
{
_tprintf(_T("Failed to allocate STMT/n"));
goto exit2;
}
// Clear Result Data
memset(resultdata, 0, sizeof(resultdata));
chunksize = clobdatalen / 15; // 15 times to put
// Step 1: Prepare
rc = SQLExecDirect(stmtHnd, sqlStmt2, SQL_NTS); // select
checkSQLErr(envHnd, conHnd, stmtHnd, rc);
// Step 2: Fetch
rc = SQLFetch(stmtHnd);
checkSQLErr(envHnd, conHnd, stmtHnd, rc);
for(dtsize=0, bufp = resultdata;
dtsize < sizeof(resultdata)/sizeof(TCHAR) && rc != SQL_NO_DATA;
dtsize += chunksize-1, bufp += chunksize-1)
{
int len; // len should contain the space for NULL termination
if (dtsize+chunksize<sizeof(resultdata)/sizeof(TCHAR))
len = chunksize;
else
len = sizeof(resultdata)/sizeof(TCHAR)-dtsize;
// Step 3: GetData
rc = SQLGetData(stmtHnd,
1,
SQL_C_TCHAR,
(SQLPOINTER)bufp,
len*sizeof(TCHAR),
&retchklen);
}
if (!_tcscmp(resultdata, clobdata))
{
_tprintf(_T("Succeeded!!/n/n"));
}
else
{
_tprintf(_T("Failed!!/n/n"));
}
This section contains the following topics:
Apply the following programming guidelines to improve the performance of an ODBC application:
Enable connection pooling if the application frequently connects and disconnects from a data source. Reusing pooled connections is extremely efficient compared to reestablishing a connection.
Minimize the number of times a statement must be prepared. Where possible, use bind parameters to make a statement reusable for different parameter values. Preparing a statement once and running it several times is much more efficient than preparing the statement for every SQLExecute.
Do not include columns in a SELECT statement of which you know the application does not retrieve; especially LONG columns. Because of the nature of the database server protocols, Oracle ODBC Driver must fetch the entire contents of a LONG column if it is included in the SELECT statement, regardless of whether the application binds the column or performs a SQLGetData operation.
If you are performing transactions that do not update the data source, then set the SQL_ATTR_ACCESS_MODE attribute of the ODBC SQLSetConnectAttr function to SQL_MODE_READ_ONLY.
If you are not using ODBC escape clauses, then set the SQL_ATTR_NOSCAN attribute of the ODBC SQLSetConnectAttr function or the ODBC SQLSetStmtAttr function to true.
Use the ODBC SQLFetchScroll function instead of the ODBC SQLFetch function for retrieving data from tables that have a large number of rows.
This section discusses the performance implications of the following ODBC data source configuration options:
Enable Result Sets
This option enables the support of returning result sets (for example, RefCursor) from procedure calls. The default is enabling the returning of result sets.
Oracle ODBC Driver must query the database server to determine the set of parameters for a procedure and their data types in order to determine if there are any RefCursor parameters. This query incurs an additional network round trip the first time any procedure is prepared and executed.
Enable LOBs
This option enables the support of inserting and updating LOBs. The default is enabled.
Oracle ODBC Driver must query the database server to determine the data types of each parameter in an INSERT or UPDATE statement to determine if there are any LOB parameters. This query incurs an additional network round trip the first time any INSERT or UPDATE is prepared and run.
|
See Also: Oracle Database SecureFiles and Large Objects Developer's Guide for more information on LOBs |
|
Note: LOB data compression enables you to compress SecureFiles to gain disk, Input-Output, and redo logging savings. This reduces costs as compression utilizes space most efficiently and improves the performance of SecureFiles as compression reduces Input-Output and redo logging.LOB data encryption provides enhanced database security. While the encrypted data is available for random reads and writes, the data is more secure. Data compression and encryption consumes some additional memory. |
Bind TIMESTAMP as DATE
Binds SQL_TIMESTAMP parameters as the appropriate Oracle Database data type. If this option is set to TRUE, then SQL_TIMESTAMP binds as the Oracle DATE data type. If this option is set to FALSE, then SQL_TIMESTAMP binds as the Oracle TIMESTAMP data type, which is the default.
Enable Closing Cursors
The SQL_CLOSE option of the ODBC function, SQLFreeStmt, is supposed to close associated cursors with a statement and discard all pending results. The application can reopen the cursor by running the statement again without doing a SQLPrepare again. A typical scenario for this would be an application that expects to be idle for a while but reuses the same SQL statement again. While the application is idle, it may want to free up any associated server resources.
The OCI, on which Oracle ODBC Driver is layered, does not support the functionality of closing cursors. Therefore, by default, the SQL_CLOSE option has no effect in Oracle ODBC Driver. The cursor and associated resources remain open on the database.
Enabling this option causes the associated cursor to be closed on the database server. However, this results in the parse context of the SQL statement being lost. The ODBC application can run the statement again without calling SQLPrepare. However, internally, Oracle ODBC Driver must prepare and run the statement all over. Enabling this option has a severe performance impact on applications that prepare a statement once and run it repeatedly.
This option should only be enabled if freeing the resources on the server is necessary.
Fetch Buffer Size
Set the Fetch Buffer Size (FetchBufferSize) in the odbc.ini file to a value specified in bytes. This value is the amount of memory needed that determines how many rows of data Oracle ODBC Driver pre-fetches at a time from an Oracle Database to the client's cache regardless of the number of rows the application program requests in a single query, thus improving performance.
There is an improvement in the response time of applications that typically fetch fewer than 20 rows of data at a time, particularly over slow network connections or from heavily loaded servers. Setting this too high can have an adverse effect on response time or consume large amounts of memory. The default is 64,000 bytes. You should choose an optimal value for the application.
When the LONG and LOB data types are present, the number of rows pre-fetched by Oracle ODBC Driver is not determined by the Fetch Buffer Size. The inclusion of the LONG and LOB data types minimizes the performance improvement and could result in excessive memory use. Oracle ODBC Driver ignores the Fetch Buffer Size and only pre-fetches a set number of rows in the presence of the LONG and LOB data types.
If a DATE column in the database is used in a WHERE clause and the column has an index, then there can be an impact on performance. For example:
SELECT * FROM EMP WHERE HIREDATE = ?
In this example, an index on the HIREDATE column could be used to make the query run quickly. However, because HIREDATE is a DATE value and Oracle ODBC Driver is supplying the parameter value as TIMESTAMP, the query optimizer of Oracle Database must apply a conversion function. To prevent incorrect results (as might happen if the parameter value had nonzero fractional seconds), the optimizer applies the conversion to the HIREDATE column resulting in the following statement:
SELECT * FROM EMP WHERE TO_TIMESTAMP(HIREDATE) = ?
However, this has the effect of disabling the use of the index on the HIREDATE column. Instead, the server performs a sequential scan of the table. If the table has many rows, then this can take a long time. As a workaround for this situation, Oracle ODBC Driver has the connection option to bind TIMESTAMP as DATE. When this option is enabled, Oracle ODBC Driver binds SQL_TIMESTAMP parameters as the Oracle DATE data type instead of the Oracle TIMESTAMP data type. This enables the query optimizer to use any index on the DATE columns.
|
Note: This option is intended only for use with Microsoft Access or other similar programs that bindDATE columns as TIMESTAMP columns. It should not be used when there are actual TIMESTAMP columns present or when data loss may occur. Microsoft Access runs such queries using whatever columns are selected as the primary key. |
When an error occurs, Oracle ODBC Driver returns the native error number, the SQLSTATE (an ODBC error code), and an error message. The driver derives this information both from errors detected by the driver and errors returned by Oracle Database.
Native Error
For errors that occur in the data source, Oracle ODBC Driver returns the native error returned to it by Oracle Database. When Oracle ODBC Driver or the Driver Manager detects an error, Oracle ODBC Driver returns a native error of zero.
SQLSTATE
For errors that occur in the data source, Oracle ODBC Driver maps the returned native error to the appropriate SQLSTATE. When Oracle ODBC Driver or the Driver Manager detects an error, it generates the appropriate SQLSTATE.
Error Message
For errors that occur in the data source, Oracle ODBC Driver returns an error message based on the message returned by Oracle Database. For errors that occur in Oracle ODBC Driver or the Driver Manager, Oracle ODBC Driver returns an error message based on the text associated with the SQLSTATE.
Error messages have the following format:
[vendor] [ODBC-component] [data-source] error-message
The prefixes in brackets ([ ]) identify the source of the error. The following table shows the values of these prefixes returned by Oracle ODBC Driver. When the error occurs in the data source, the vendor and ODBC-component prefixes identify the vendor and name of the ODBC component that received the error from the data source.
| Error Source | Prefix | Value |
|---|---|---|
| Driver Manager | [vendor]
[ODBC-component] [data-source] | [unixODBC]
[Driver Manager] Not applicable |
| Oracle ODBC Driver | [vendor]
[ODBC-component] [data-source] | [ORACLE]
[Oracle ODBC Driver] Not applicable |
| Oracle Database | [vendor]
[ODBC-component] [data-source] | [ORACLE]
[Oracle ODBC Driver] [Oracle OCI] |
For example, if the error message does not contain the Ora prefix shown in the following format, then error is an Oracle ODBC Driver error and should be self-explanatory.
[Oracle][ODBC]Error message text here
If the error message contains the Ora prefix shown in the following format, then it is not an Oracle ODBC Driver error.
[Oracle][ODBC][Ora]Error message text here
|
Note: Although the error message contains theORA- prefix, the actual error may originate from one of several sources. |
If the error message text starts with the ORA- prefix, then you can obtain more information about the error in Oracle Database documentation.
This guide provides platform-specific information about administering and configuring Oracle Database 11g Release 2 (11.2) on the following platforms:
IBM AIX on POWER Systems
HP-UX
Linux
Oracle Solaris
This guide supplements the Oracle Database Administrator's Guide.
This guide is intended for anyone responsible for administering and configuring Oracle Database 11g Release 2 (11.2). If you are configuring Oracle RAC, then refer to Oracle Real Application Clusters Administration and Deployment Guide.
For information about Oracle's commitment to accessibility, visit the Oracle Accessibility Program website at http://www.oracle.com/pls/topic/lookup?ctx=acc&id=docacc.
Access to Oracle Support
Oracle customers have access to electronic support through My Oracle Support. For information, visit http://www.oracle.com/pls/topic/lookup?ctx=acc&id=info or visit http://www.oracle.com/pls/topic/lookup?ctx=acc&id=trs if you are hearing impaired.
Refer to the appropriate section for a listing of platform specific Oracle Database 11g documentation:
IBM AIX on POWER Systems Documentation
Oracle Database
Oracle Database Installation Guide for IBM AIX on POWER Systems (64-Bit)
Oracle Database Installation Guide for IBM AIX on POWER Systems (64-Bit)
Oracle Database Quick Installation Guide for IBM AIX on POWER Systems (64-Bit)
Oracle Grid Infrastructure Installation Guide for IBM AIX on POWER Systems
Oracle Real Application Clusters Installation Guide for Linux and UNIX
Oracle Database Client
Oracle Database Examples
HP-UX Documentation
Oracle Database
Oracle Database Client
Oracle Database Examples
Linux Documentation
Oracle Database
Oracle Real Application Clusters Installation Guide for Linux and UNIX
Oracle Enterprise Manager Grid Control Basic Installation Guide
Oracle Database Client
Oracle Database Examples
Oracle Solaris Documentation
Oracle Database
Oracle Database Quick Installation Guide for Oracle Solaris on SPARC (64-Bit)
Oracle Database Quick Installation Guide for Oracle Solaris on x86-64 (64-Bit)
Oracle Grid Infrastructure Installation Guide for Solaris Operating System
Oracle Real Application Clusters Installation Guide for Linux and UNIX
Oracle Database Client
Oracle Database Examples
For important information that was not available when this book was released, refer to the release notes for the platform. The release notes for Oracle Database are updated regularly. You can get the most recent version from Oracle Technology Network at
http://www.oracle.com/technetwork/indexes/documentation/index.html
The following text conventions are used in this document:
| Convention | Meaning |
|---|---|
| boldface | Boldface type indicates graphical user interface elements associated with an action, or terms defined in text or the glossary. |
| italic | Italic type indicates book titles, emphasis, or placeholder variables for which you supply particular values. |
monospace | Monospace type indicates commands within a paragraph, URLs, code in examples, text that appears on the screen, or text that you enter. |
UNIX command syntax appears in monospace font. The dollar character ($), number sign (#), or percent character (%) are UNIX command prompts. Do not enter them as part of the command. The following command syntax conventions are used in this guide:
| Convention | Description |
|---|---|
| backslash \ | A backslash is the UNIX command continuation character. It is used in command examples that are too long to fit on a single line. Enter the command as displayed (with a backslash) or enter it on a single line without a backslash:
dd if=/dev/rdsk/c0t1d0s6 of=/dev/rst0 bs=10b \ count=10000 |
| braces { } | Braces indicate required items:
.DEFINE {macro1}
|
| brackets [ ] | Brackets indicate optional items:
cvtcrt termname [outfile] |
| ellipses ... | Ellipses indicate an arbitrary number of similar items:
CHKVAL fieldname value1 value2 ... valueN |
| italic | Italic type indicates a variable. Substitute a value for the variable:
library_name
|
| vertical line | | A vertical line indicates a choice within braces or brackets:
FILE filesize [K|M]
|
The names of some UNIX operating systems have been shortened in this guide. These are:
| Operating System | Abbreviated Name |
|---|---|
| IBM AIX on POWER Systems | AIX |
HP-UX PA-RISC (64-bit) HP-UX Itanium | HP-UX
Note: Where the information for HP-UX is different on a particular architecture, this is noted in the text. |
Linux x86 Linux x86-64 IBM: Linux on System z | Linux
Note: Where the information for Linux is different on a particular architecture, this is noted in the text. |
Oracle Solaris on SPARC (64-Bit) Oracle Solaris on x86-64 (64-bit) | Solaris
Note: Where the information for Solaris is different on a particular architecture, this is noted in the text. |
The documentation for this release includes platform-specific documentation and generic product documentation. Platform-specific documentation includes information about installing, configuring, and using Oracle products on a particular platform. The documentation is available in Adobe portable document format (PDF) and HTML format.
To access the platform-specific documentation on installation media, use a Web browser to open the welcome.html file in the top-level directory.
To access all Oracle documentation, see Oracle Technology Network Web site:
http://www.oracle.com/technetwork/indexes/documentation/index.html
|
Note: Platform-specific documentation is current at the time of release. For the latest information, Oracle recommends you to go to Oracle Technology Network Web site. |
This chapter guides Linux system administrators to configure Very Large Memory configurations and HugePages on Red Hat Enterprise Linux/ Oracle Linux.
This chapter contains the following sections:
Very Large Memory (VLM) configurations allow a 32-bit Oracle Database to access more than 4GB RAM that is traditionally available to Linux applications. The Oracle VLM option for 32-bit creates a large database buffer cache using an in-memory file system (/dev/shm). Other parts of the SGA are allocated from regular memory. VLM configurations improve database performance by caching more database buffers in memory, which significantly reduces the disk I/O compared to configurations without VLM. This chapter shows how to increase the SGA memory using VLM on a 32-bit computer.
|
Note: The contents documented in this section apply only to 32-bit Linux operating system. With a 64-bit architecture, VLM support is available natively. All 64-bit Linux operating systems use the physical memory directly, as the maximum available virtual address space is 16 EB (exabyte = 2^60 bytes.) |
This section includes the following topics:
With 32-bit architectures, VLM is accessed through a VLM window of a specific size. The VLM window is a data structure in the process address space that provides access to the whole virtual address space from a window of a specific size. On 32-bit Linux, you must set the parameter USE_INDIRECT_DATA_BUFFERS=TRUE, and mount a shmfs or tmpfs or ramfs type of in-memory filesystem over /dev/shm to increase the usable address space.
The following are some of the prerequisites for implementing VLM on a 32-bit operating system:
The computer on which Oracle Database is installed must have more than 4GB of memory.
The computer must be configured to use a kernel with PAE support upon startup.
The USE_INDIRECT_DATA_BUFFERS=TRUE must be present in the initialization parameter file for the database instance that uses VLM support.
Initialization parameters DB_BLOCK_BUFFERS and DB_BLOCK_SIZE must be set to values you have chosen for the Oracle Database.
In a typical 32-bit Linux kernel, one can create an SGA of up to 1.7GB size. Using a Linux Hugemem kernel enables the creation of an SGA of upto 3.6GB size. To go beyond 3.6GB on a 32-bit kernel, you must use the VLM feature.
The following are the methods to increase SGA limits on a 32-bit computer:
Red Hat Enterprise Linux 4 and Oracle Linux 4 include a new kernel known as the Hugemem kernel. The Hugemem kernel feature is also called a 4GB-4GB Split Kernel as it supports a 4GB per process user space (versus 3GB for the other kernels), and a 4GB direct kernel space. Using this kernel enables RHEL 4/Oracle Linux 4 to run on systems with up to 64GB of main memory. The Hugemem kernel is required to use all the memory in system configurations containing more than 16GB of memory. The Hugemem kernel can run configurations with less memory.
A classic 32-bit 4GB virtual address space is split 3GB for user processes and 1GB for the kernel. The new scheme (4GB/4GB) permits 4GB of virtual address space for the kernel and almost 4GB for each user process. Due to this scheme with hugemem kernel, 3.6GB of SGA can be created without using the indirect data buffer method.
|
Note: Red Hat Enterprise Linux 5/ Oracle Linux 5 on 32-bit does not have the hugemem kernel. It supports only the 3GB user process/ 1GB kernel split. It has a PAE kernel that supports systems with more than 4GB of RAM and reliably upto 16GB. Since this has a 3GB/1GB kernel split, the system may run out of lowmem if the system's load consumes lots of lowmem. There is no equivalent kernel for hugemem in Enterprise Linux 5 and one is recommended to either use Enterprise Linux 4 with hugemem or go for 64-bit. |
The Hugemem kernel on large computers ensures better stability as compared to the performance overhead of address space switching.
Run the following command to determine if you are using the Hugemem kernel:
$ uname -r 2.6.9-5.0.3.ELhugemem
If you use only Hugemem kernels on 32-bit systems, then the SGA size can be increased but not significantly. Refer to section "Hugemem Kernel", for more information.
|
Note: Red Hat Enterprise Linux 5/ Oracle Linux 5 does not support the hugemem kernel. It supports a PAE kernel that can be used to implement Very Large Memory (VLM) as long as the physical memory does not exceed 16GB. |
This section shows how the SGA can be significantly increased by using Hugemem kernel with VLM on 32-bit systems.
The SGA can be increased to about 62GB (depending on block size) on a 32-bit system with 64GB RAM. A processor feature called Page Address Extension (PAE) permits you to physically address 64GB of RAM. Since PAE does not enable a process or program to either address more than 4GB directly, or have a virtual address space larger than 4GB, a process cannot attach to shared memory directly. To address this issue, a shared memory filesystem (memory-based filesystem) must be created which can be as large as the maximum allowable virtual memory supported by the kernel. With a shared memory filesystem processes can dynamically attach to regions of the filesystem allowing applications like Oracle to have virtually a much larger shared memory on 32-bit operating systems. This is not an issue on 64-bit operating systems.
VLM moves the database buffer cache part of the SGA from the System V shared memory to the shared memory filesystem. It is still considered one large SGA but it consists now of two different operating system shared memory entities. VLM uses 512MB of the non-buffer cache SGA to manage VLM. This memory area is needed for mapping the indirect data buffers (shared memory filesystem buffers) into the process address space since a process cannot attach to more than 4GB directly on a 32-bit system.
|
Note: USE_INDIRECT_DATA_BUFFERS=TRUE must be present in the initialization parameter file for the database instance that use Very Large Memory support. If this parameter is not set, then Oracle Database 11g Release 2 (11.2) or later behaves in the same way as previous releases.
You must also manually set the initialization parameters |
For example, if the non-buffer cache SGA is 2.5GB, then you will only have 2GB of non-buffer cache SGA for shared pool, large pool, and redo log buffer since 512MB is used for managing VLM. It is not recommended to use VLM if buffer cache size is less than 512MB.
In RHEL 4/ Oracle Linux 4 there are two different memory file systems that can be used for VLM:
tmpfs or shmfs: mount a shmfs with a certain size to /dev/shm, and set the correct permissions. For tmpfs you do not need to specify a size. Tmpfs or shmfs allocated memory is pageable.
For example:
Example Mount shmfs: # mount -t shm shmfs -o size=20g /dev/shm Edit /etc/fstab: shmfs /dev/shm shm size=20g 0 0 OR Example Mount tmpfs: # mount –t tmpfs tmpfs /dev/shm Edit /etc/fstab: none /dev/shm tmpfs defaults 0 0
ramfs: ramfs is similar to shmfs, except that pages are not pageable or swappable. This approach provides the commonly desired effect. ramfs is created by:
umount /dev/shm mount -t ramfs ramfs /dev/shm
Complete the following procedure to configure Very Large Memory on Red Hat Enterprise Linux 4/ Oracle Linux 4 using ramfs:
Log in as a root user:
sudo -sh Password:
Edit the /etc/rc.local file and add the following entries to it to configure the computer to mount ramfs over the /dev/shm directory, whenever you start the computer:
umount /dev/shm mount -t ramfs ramfs /dev/shm chown oracle:oinstall /dev/shm
In the preceding commands, oracle is the owner of Oracle software files and oinstall is the group for Oracle owner account. If the new configuration disables /etc/rc.local file or you start an instance of Oracle database using a Linux service script present under the /etc/init.d file, then you can add those entries in the service script too.
Note, this configuration will make ramfs ready even before your system autostarts crucial Oracle Database instances. The commands can also be included in your startup scripts. It is important that you test the commands extensively by repeated restart action, after you complete configuring the computer using the following steps:
Restart the server.
Log in as a root user.
Run the following command to check if the /dev/shm directory is mounted with the ramfs type:
/dev/shm directory is mounted with the ramfs type: # mount | grep shm ramfs on /dev/shm type ramfs (rw)
Run the following command to check the permissions on the /dev/shm directory:
# ls -ld /dev/shm drwxr-xr-x 3 oracle oinstall 0 Jan 13 12:12 /dev/shm
Edit the /etc/security/limits.conf file and add the following entries to it to increase the max locked memory limit:
soft memlock 3145728 hard memlock 3145728
Switch to the oracle user:
# sudo - oracle Password:
Run the following command to check the max locked memory limit:
$ ulimit -l 3145728
Complete the following procedure to configure instance parameters for Very Large Memory:
Replace the DB_CACHE_SIZE, DB_xK_CACHE_SIZE, sga_target, and memory_target parameters with DB_BLOCK_BUFFERS parameter.
Add the USE_INDIRECT_DATA_BUFFERS=TRUE parameter.
Configure SGA size according to the SGA requirements.
Remove SGA_TARGET, MEMORY_TARGET, or MEMORY_MAX_TARGET parameters, if set.
Start the database instance.
Run the following commands to check the memory allocation:
$ ls -l /dev/shm $ ipcs -m
|
See Also: "Configuring HugePages on Red Hat Enterprise Linux and Oracle Linux" section for more information about HugePages. |
Following are the limitations of running a computer in the Very Large Memory mode:
You cannot use Automatic Memory Management (AMM) while implementing VLM using ramfs, because AMM works on dynamic SGA tuning. With AMM swapping is possible. For example, you can unmap the unused SGA space and map it to PGA. Dynamic SGA and multiple block size are not supported with Very Large Memory because ramfs is not swappable. To enable Very Large Memory, you must ensure that you set the value of MEMORY_TARGET to zero.
VLM can be implemented only if Database Buffer Cache size is greater than 512MB.
HugePages is a feature integrated into the Linux kernel 2.6. It is a method to have larger page size that is useful for working with very large memory. HugePages is useful for both 32-bit and 64-bit configurations. HugePage sizes vary from 2MB to 256MB, depending on the kernel version and the hardware architecture. For Oracle Databases, using HugePages reduces the operating system maintenance of page states, and increases Translation Lookaside Buffer (TLB) hit ratio.
This section includes the following topics:
Without HugePages, the operating system keeps each 4KB of memory as a page, and when it is allocated to the SGA, then the lifecycle of that page (dirty, free, mapped to a process, and so on) is kept up to date by the operating system kernel.
With HugePages, the operating system page table (virtual memory to physical memory mapping) is smaller, since each page table entry is pointing to pages from 2MB to 256MB. Also, the kernel has fewer pages whose lifecyle must be monitored.
|
Note: 2MB size of HugePages is available with Linux x86-64, Linux x86, and IBM: Linux on System z. |
The following are the advantages of using HugePages:
Increased performance through increased TLB hits.
Pages are locked in memory and are never swapped out which guarantees that shared memory like SGA remains in RAM.
Contiguous pages are preallocated and cannot be used for anything else but for System V shared memory (for example, SGA)
Less bookkeeping work for the kernel for that part of virtual memory due to larger page sizes
Complete the following steps to configure HugePages on the computer:
Edit the memlock setting in the /etc/security/limits.conf file. The memlock setting is specified in KB and set slightly lesser than the installed RAM. For example, if you have 64GB RAM installed, add the following entries to increase the max locked memory limit:
* soft memlock 60397977 * hard memlock 60397977
You can also set the memlock value higher than your SGA requirements.
Login as the oracle user again and run the ulimit -l command to verify the new memlock setting:
$ ulimit -l 60397977
Run the following command to display the value of Hugepagesize variable:
$ grep Hugepagesize /proc/meminfo
Complete the following procedure to create a script that computes recommended values for hugepages configuration for the current shared memory segments:
|
Note: Following is an example that may require modifications. |
Create a text file named hugepages_settings.sh.
Add the following content in the file:
#!/bin/bash
#
# hugepages_settings.sh
#
# Linux bash script to compute values for the
# recommended HugePages/HugeTLB configuration
#
# Note: This script does calculation for all shared memory
# segments available when the script is run, no matter it
# is an Oracle RDBMS shared memory segment or not.
# Check for the kernel version
KERN=`uname -r | awk -F. '{ printf("%d.%d\n",$1,$2); }'`
# Find out the HugePage size
HPG_SZ=`grep Hugepagesize /proc/meminfo | awk {'print $2'}`
# Start from 1 pages to be on the safe side and guarantee 1 free HugePage
NUM_PG=1
# Cumulative number of pages required to handle the running shared memory segments
for SEG_BYTES in `ipcs -m | awk {'print $5'} | grep "[0-9][0-9]*"`
do
MIN_PG=`echo "$SEG_BYTES/($HPG_SZ*1024)" | bc -q`
if [ $MIN_PG -gt 0 ]; then
NUM_PG=`echo "$NUM_PG+$MIN_PG+1" | bc -q`
fi
done
# Finish with results
case $KERN in
'2.4') HUGETLB_POOL=`echo "$NUM_PG*$HPG_SZ/1024" | bc -q`;
echo "Recommended setting: vm.hugetlb_pool = $HUGETLB_POOL" ;;
'2.6') echo "Recommended setting: vm.nr_hugepages = $NUM_PG" ;;
*) echo "Unrecognized kernel version $KERN. Exiting." ;;
esac
# End
Run the following command to change the permission of the file:
$ chmod +x hugepages_settings.sh
Run the hugepages_settings.sh script to compute the values for hugepages configuration:
$ ./hugepages_settings.sh
Set the following kernel parameter:
# sysctl -w vm.nr_hugepages=value_displayed_in_step_5
To make the value of the parameter available for every time you restart the computer, edit the /etc/sysctl.conf file and add the following entry:
vm.nr_hugepages=value_displayed_in_step_5
Restart the server.
|
Note: To check the availablehugepages, run the following command:
$ grep Huge /proc/meminfo |
Following are the limitations of using HugePages:
The Automatic Memory Management (AMM) and HugePages are not compatible. With AMM the entire SGA memory is allocated by creating files under /dev/shm. When Oracle Database allocates SGA that way HugePages are not reserved. You must disable AMM on Oracle Database to use HugePages.
If you are using VLM in a 32-bit environment, then you cannot use HugePages for the Database Buffer cache. HugePages can be used for other parts of SGA like shared_pool, large_pool, and so on. Memory allocation for VLM (buffer cache) is done using shared memory file systems (ramfs/tmpfs/shmfs). HugePages does not get reserved or used by the memory file systems.
HugePages are not subject to allocation or release after system startup, unless a system administrator changes the HugePages configuration by modifying the number of pages available, or the pool size. If the space required is not reserved in memory during system startup, then HugePages allocation fails.
This chapter describes how to use Oracle precompilers and the Oracle Call Interface. It contains the following sections:
|
Note: To use the demonstrations described in this chapter, install the Oracle Database Examples included on the Oracle Database 11g Examples media. |
Oracle precompilers are application development tools that are used to combine SQL statements for an Oracle Database with programs written in a high-level language. Oracle precompilers are compatible with ANSI SQL and are used to develop and open customized applications that run with Oracle Database or any other ANSI SQL database management system.
This section contains the following topics:
|
Note: ORACLE_HOME in this section refers to ORACLE_HOME that is created while installing Oracle Database Client 11g by using the Administrator Install type. |
Configuration files for the Oracle precompilers are located in the $ORACLE_HOME/precomp/admin directory.
Table 6-1 lists the names of the configuration files for each precompiler.
Use the $ORACLE_HOME/precomp/lib/ins_precomp.mk make file to relink all precompiler executables. To manually relink a particular precompiler executable, enter the following command:
$ make -f ins_precomp.mk relink exename = executable_name
This command creates the new executable in the $ORACLE_HOME/precomp/lib directory, and then moves it to the $ORACLE_HOME/bin directory.
In the preceding example, replace executable with one of the product executables listed in Table 6-2.
Table 6-2 lists the executables for Oracle Precompilers.
Table 6-2 Executables for Oracle Precompilers
| Product | Executable |
|---|---|
|
Pro*C/C++ 32 bit (HP-UX and IBM: Linux on System z) |
proc |
|
Pro*COBOL (AIX, HP-UX, and Solaris) |
|
|
Pro*COBOL 32-bit (AIX, HP-UX, Solaris, and IBM: Linux on System z) |
|
|
Pro*FORTRAN (HP-UX) |
|
|
Pro*FORTRAN 32-bit (AIX, HP-UX, and Solaris) |
|
|
SQL*Module for Ada (AIX) |
|
The README files describe changes made to the precompiler since the last release.
Table 6-3 lists the location of the precompiler README files.
The following issues are common to all precompilers:
Uppercase to Lowercase Conversion
In languages other than C, the compiler converts an uppercase function or subprogram name to lowercase. This can cause a No such user exists error message. If you receive this error message, then verify that the case of the function or subprogram name in the option file matches the case used in the IAPXTB table.
Precompilers and vendor-supplied debuggers can be incompatible. Oracle does not guarantee that a program run using a debugger performs the same way when it is run without the debugger.
Value of IRECLEN and ORECLEN parameters
The IRECLEN and ORECLEN parameters do not have maximum values.
You can statically or dynamically link Oracle libraries with precompiler and OCI or OCCI applications. With static linking, the libraries and objects of the whole application are linked into a single executable program. As a result, application executables can become very large.
With dynamic linking, the executing code is partly stored in the executable program and partly stored in libraries that are linked dynamically by the application at run time. Libraries that are linked at run time are called dynamic or shared libraries. The benefits of dynamic linking are:
Reduced disk space requirements: Multiple applications or calls to the same application can use the same dynamic libraries.
Reduced main memory requirements: The same dynamic library image is loaded into main memory only once, and it can be shared by multiple application.
The client shared and static libraries are located in $ORACLE_HOME/lib. If you use the Oracle-provided demo_product.mk file to link an application, then the client shared library is linked by default.
If the shared library path environment variable setting does not include the directory that contains the client shared library, then you may see an error message similar to one of the following lines when starting an executable:
Cannot load library libclntsh.a cannot open shared library: .../libclntsh.sl.10.1 libclntsh.so.10.1: can't open file: errno=2 can't open library: .../libclntsh.dylib.10.1 Cannot map libclntsh.so
To avoid this error, set the shared library path environment variable to specify the appropriate directory. The following table shows sample settings for this environment variable name. If the platform supports both 32-bit and 64-bit applications, then ensure that you specify the correct directory, depending on the application that you want to run.
| Platform | Environment Variable | Sample Setting |
|---|---|---|
| AIX (32-bit applications) | LIBPATH | $ORACLE_HOME/lib |
| AIX (64-bit applications) | LIBPATH | $ORACLE_HOME/lib |
| HP-UX (32-bit applications) | SHLIB_PATH | $ORACLE_HOME/lib |
| HP-UX (64-bit applications) and Linux | LD_LIBRARY_PATH | $ORACLE_HOME/lib |
| Solaris (32-bit applications) | LD_LIBRARY_PATH | $ORACLE_HOME/lib |
| Solaris (64-bit applications) | LD_LIBRARY_PATH | $ORACLE_HOME/lib |
| IBM: Linux on System z (32-bit applications) | LD_LIBRARY_PATH | $ORACLE_HOME/lib |
| IBM: Linux on System z (64-bit applications) | LD_LIBRARY_PATH | $ORACLE_HOME/lib |
The client shared library is created automatically during installation. If you must re-create it, then:
Quit all client applications that use the client shared library, including all Oracle client applications such as SQL*Plus and Oracle Recovery Manager.
Log in as the oracle user, and run the following command:
$ $ORACLE_HOME/bin/genclntsh
Nonthreaded Client Shared Library
|
Note: The information in this section applies to HP-UX systems. |
On HP-UX, you can use a non-threaded client shared library. However, you cannot use this library with any OCI application that uses or has a dependency on threads.
To use this library for applications that do not use threads, run the following command to build the OCI application for 32 and 64-bit:
$ make -f demo_rdbms.mk build_nopthread EXE=oci02 OBJS=oci02.o
The following table identifies the bit lengths (31-bit, 32-bit, or 64-bit) supported for client applications:
|
Note: Starting with Oracle Database 11g Release 2 (11.2), 32-bit precompiler, 32-bit client executables, and libraries are not available in the 64-bit Oracle database installation. These are installed as part of the Oracle Database Client Installation. |
| Client Application Type | Supported Platforms |
|---|---|
| 32-bit only | Linux x86 |
| 32-bit and 64-bit | AIX, HP-UX PA-RISC, Linux x86-64, SPARC, HP-UX Itanium, Solaris x86-64, and IBM: Linux on System z |
The following table lists the 32-bit and 64-bit client shared libraries:
|
Note: Starting with Oracle Database 11g Release 2 (11.2), 32-bit and 64-bit Oracle Database Clients are installed in separate Oracle homes. |
| Platform | 32-Bit (or 31-Bit) Client Shared Library | 64-Bit Client Shared Library |
|---|---|---|
| AIX |
$ORACLE_HOME/lib/libclntsh.a $ORACLE_HOME/lib/libclntsh.so |
$ORACLE_HOME/lib/libclntsh.a $ORACLE_HOME/lib/libclntsh.so |
| HP-UX PA-RISC
HP-UX Itanium |
$ORACLE_HOME/lib/libclntsh.sl |
$ORACLE_HOME/lib/libclntsh.sl |
| Linux x86-64, Solaris, Solaris x86-64, and IBM: Linux on System z |
$ORACLE_HOME/lib/libclntsh.so |
$ORACLE_HOME/lib/libclntsh.so |
To implement a mixed word-size installation:
Run the following command to generate the 32-bit and 64-bit client shared libraries:
$ $ORACLE_HOME/bin/genclntsh
Include the paths of the required 32-bit and 64-bit client shared libraries in one of the following environment variables, depending on the platform:
| Platform | Environment Variable |
|---|---|
| AIX | LIBPATH |
| HP-UX (32-bit client applications) | SHLIB_PATH |
| HP-UX, Linux x86, Linux x86-64, Solaris, and IBM: Linux on System z | LD_LIBRARY_PATH |
Building 32-Bit Pro*C and OCI Customer Applications
If the operating system supports both Pro*C and Oracle Call Interface (OCI) customer applications, then you can find more information about building Pro*C and OCI applications in the following files:
| For Information About. . . | Refer to the Following Make Files. . . |
|---|---|
| Building Pro*C applications | $ORACLE_HOME/precomp/demo/proc/demo_proc.mk |
| Building OCI applications | $ORACLE_HOME/rdbms/demo/demo_rdbms.mk |
Before you use the Pro*C/C++ precompiler, verify that the correct version of the operating system compiler is properly installed.
|
See Also:
|
This section contains the following topics:
Demonstration programs are provided to show the features of the Pro*C/C++ precompiler. There are three types of demonstration programs: C, C++, and Object programs. All demonstration programs are located in the $ORACLE_HOME/precomp/demo/proc directory. By default, all programs are dynamically linked with the client shared library.
To run the demonstration programs, the programs require the demonstration tables created by the $ORACLE_HOME/sqlplus/demo/demobld.sql script to exist in the JONES schema with a password.
|
Note: You must unlock the JONES account and set the password before creating the demonstrations. |
Use the demo_proc.mk make file, which is located in the $ORACLE_HOME/precomp/demo/proc/ directory, to create the demonstration programs. For example, to precompile, compile, and link the sample1 demonstration program, run the following command:
|
Note: On AIX systems, to ensure that the demonstration programs compile correctly, include the-r option of the make command in the following examples. For example:
$ make -r -f demo_proc.mk sample1 |
$ make -f demo_proc.mk sample1€ÿ
To create all the C demonstration programs for Pro*C/C++, run the following command:
$ make -f demo_proc.mk samples
To create all the C++ demonstration programs for Pro*C/C++, run the following command:
$ make -f demo_proc.mk cppsamples
To create all the Object demonstration programs for Pro*C/C++, run the following command:
$ make -f demo_proc.mk object_samples
Some demonstration programs require you to run a SQL script, located in the $ORACLE_HOME/precomp/demo/sql directory. If you do not run the script, then a message prompting you to run it is displayed.
To build a demonstration program and run the corresponding SQL script, include the make macro argument RUNSQL=run at the command line. For example, to create the sample9 demonstration program and run the required $ORACLE_HOME/precomp/demo/sql/sample9.sql script, run the following command:
$ make -f demo_proc.mk sample9 RUNSQL=run
To create all the Object demonstration programs and run all the required SQL scripts, run the following command:
$ make -f demo_proc.mk object_samples RUNSQL=run
You can use the $ORACLE_HOME/precomp/demo/proc/demo_proc.mk make file to create user programs. This make file builds either 32-bit or 64-bit user programs. You can also use the demo_proc32.mk make file to build 32-bit user programs. The following table shows the make files that you can use to build 32-bit and 64-bit user programs with Pro*C/C++:
| Platform | 64-bit Make File | 32-Bit Make File |
|---|---|---|
| AIX, HP-UX, Linux x86-64, Solaris x86-64 and Solaris | demo_proc.mk | demo_proc32.mk |
| Linux x86 | NA | demo_proc.mk |
|
See Also: The make file for more information about creating user programs |
|
Note: On AIX systems, to ensure that the programs compile correctly, specify the-r option for the make command used in the following examples. |
To create a program by using the demo_proc.mk make file, run a command similar to the following:
$ make -f demo_proc.mk target OBJS="objfile1 objfile2 ..." EXE=exename
In this example:
target is the make file target that you want to use
objfilen is the object file to link the program
exename is the executable program
For example, to create the program myprog from the Pro*C/C++ source file myprog.pc, run one of the following commands, depending on the source and the type of executable that you want to create:
For C source dynamically linked with the client shared library, run the following command:
$ make -f demo_proc.mk build OBJS=myprog.o EXE=myprog
For C source statically linked with the client shared library, run the following command:
$ make -f demo_proc.mk build_static OBJS=myprog.o EXE=myprog
For C++ source dynamically linked with the client shared library, run the following command:
$ make -f demo_proc.mk cppbuild OBJS=myprog.o EXE=myprog
For C++ source statically linked with the client shared library, run the following command:
$ make -f demo_proc.mk cppbuild_static OBJS=myprog.o EXE=myprog
Table 6-4 shows the naming conventions for the Pro*COBOL precompiler.
Table 6-4 Pro*COBOL Naming Conventions
| Item | Naming Convention |
|---|---|
|
Executable |
|
|
Demonstration directory |
|
|
Make file |
|
Pro*COBOL supports statically linked, dynamically linked, or dynamically loadable programs. Dynamically linked programs use the client shared library. Dynamically loadable programs use the rtsora executable located in the $ORACLE_HOME/bin directory.
This section contains the following topics:
This section describes the environment variables required by Pro*COBOL:
To use the Micro Focus Server Express COBOL compiler, you must set the COBDIR and PATH environment variables and the shared library path environment variable.
|
See Also: The "Client Shared and Static Libraries" section for information about the shared library path environment variable |
Set the COBDIR environment variable to the directory where the compiler is installed. For example, if the compiler is installed in the /opt/lib/cobol directory, then run the following command:
Bourne, Bash, or Korn shell:
$ COBDIR=/opt/lib/cobol $ export COBDIR
C shell:
% setenv COBDIR /opt/lib/cobol
Set the PATH environment variable to include the $COBDIR/bin directory:
Bourne, Bash, or Korn shell:
$ PATH=$COBDIR/bin:$PATH $ export PATH
C shell:
% setenv PATH ${COBDIR}/bin:${PATH}
Set the LIBPATH, LD_LIBRARY_PATH, or SHLIB_PATH environment variable to the directory where the compiler library is installed. For example, if the platform uses the LD_LIBRARY_PATH environment variable and the compiler library is installed in the $COBDIR/coblib directory, then run the following command:
Bourne, Bash, or Korn shell:
$ LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:$COBDIR/coblib
$ export LD_LIBRARY_PATH
C shell:
% setenv LD_LIBRARY_PATH ${LD_LIBRARY_PATH}:$COBDIR/coblib
To use the Acucorp ACUCOBOL-GT COBOL compiler, you must set the A_TERMCAP, A_TERM, PATH, and LD_LIBRARY_PATH environment variables. If the LD_LIBRARY_PATH environment variable setting does not include the correct directory, then an error message similar to the following is displayed when you compile or run a program:
runcbl: error while loading shared libraries: libclntsh.so: cannot open shared object file: No such file or directory
Set the A_TERMCAP environment variable to specify the location of the a_termcap file and set the A_TERM environment variable to specify a supported terminal from that file. For example:
Bourne, Bash, or Korn shell:
$ A_TERMCAP=/opt/COBOL/etc/a_termcap $ A_TERM=vt100 $ export A_TERMCAP A_TERM
C shell:
% setenv A_TERMCAP /opt/COBOL/etc/a_termcap % setenv A_TERM vt100
Set the PATH environment variable to include the /opt/COBOL/bin directory:
Bourne, Bash, or Korn shell:
$ PATH=/opt/COBOL/bin:$PATH $ export PATH
C shell:
% setenv PATH opt/COBOL/bin:${PATH}
|
Note: On AIX, theLIBPATH variable is the LD_LIBRARY_PATH variable equivalent. You must use the LIBPATH variable on AIX instead of the LD_LIBRARY_PATH variable in the following commands. |
Set the LD_LIBRARY_PATH environment variable to the directory where the compiler library is installed. For example, if the compiler library is installed in the /opt/COBOL/lib directory, then run the following command:
Bourne, Bash, or Korn shell:
$ LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:/opt/COBOL/lib
$ export LD_LIBRARY_PATH
C shell:
% setenv LD_LIBRARY_PATH ${LD_LIBRARY_PATH}:/opt/COBOL/lib
Oracle provides its own complete run-time system, called rtsora, to run dynamically loadable Pro*COBOL programs. Use the rtsora run-time system instead of the cobrun run-time system to run dynamically loadable Pro*COBOL programs. If you attempt to run a Pro*COBOL program with cobrun, then an error message similar to the following is displayed:
$ cobrun sample1.gnt Load error : file 'SQLADR' error code: 173, pc=0, call=1, seg=0 173 Called program file not found in drive/directory
Demonstration programs are provided to show the features of the Pro*COBOL precompiler. The demonstration programs are located in the $ORACLE_HOME/precomp/demo/procob2 directory. By default, all programs are dynamically linked with the client shared library.
To run the demonstration programs, the programs require the demonstration tables created by the $ORACLE_HOME/sqlplus/demo/demobld.sql script to exist in the JONES schema with a password.
|
Note: You must unlock the JONES account and set the password before creating the demonstrations. |
Use the following make file to create the demonstration programs:
$ORACLE_HOME/precomp/demo/procob2/demo_procob.mk
To precompile, compile, and link the sample1 demonstration program for Pro*COBOL, run the following command:
$ make -f demo_procob.mk sample1
To create the Pro*COBOL demonstration programs, run the following command:
$ make -f demo_procob.mk samples
To create and run a dynamically loadable sample1.gnt program to be used with the rtsora run-time system, run the following command:
$ make -f demo_procob.mk sample1.gnt $ rtsora sample1.gnt
Some demonstration programs require you to run a SQL script, which is located in the $ORACLE_HOME/precomp/demo/sql directory. If you do not run the script, then a message requesting you to run it is displayed.
To build a demonstration program and run the corresponding SQL script, include the make macro argument RUNSQL=run in the command. For example, to create the sample9 demonstration program and run the required $ORACLE_HOME/precomp/demo/sql/sample9.sql script, run the following command:
$ make -f demo_procob.mk sample9 RUNSQL=run
To create the Pro*COBOL demonstration programs and run all required SQL scripts, run the following command:
$ make -f demo_procob.mk samples RUNSQL=run
You can use the $ORACLE_HOME/precomp/demo/procob2/demo_procob.mk make file to create user programs. This make file builds either 32-bit or 64-bit user programs. You can also use the demo_procob.mk make file to build 32-bit (or 31-bit) user programs. The following table shows the make files that you can use to build 32-bit (or 31-bit) and 64-bit user programs with Pro*COBOL:
| Platform | Make File |
|---|---|
| AIX, HP-UX, Linux x86-64, Solaris, IBM: Linux on System z, and Linux x86 | demo_procob.mk |
|
See Also: The make file for more information about creating user programs |
To create a program using the demo_procob.mk make file, run a command similar to the following:
$ make -f demo_procob.mk target COBS="cobfile1 cobfile2 ..." EXE=exename
In this example:
target is the make file target that you want to use
cobfilen is the COBOL source file for the program
exename is the executable program
For example, to create the program myprog, run one of the following commands, depending on the source and type of executable that you want to create:
For COBOL source, dynamically linked with the client shared library, run the following command:
$ make -f demo_procob.mk build COBS=myprog.cob EXE=myprog
For COBOL source, statically linked, run the following command:
$ make -f demo_procob.mk build_static COBS=myprog.cob EXE=myprog
For COBOL source, dynamically loadable for use with rtsora, run the following command:
$ make -f demo_procob.mk myprog.gnt
The FORMAT precompiler option specifies the format of input lines for COBOL. If you specify the default value ANSI, then columns 1 to 6 contain an optional sequence number, column 7 indicates comments or continuation lines, paragraph names begin in columns 8 to 11, and statements begin in columns 12 to 72.
If you specify the value TERMINAL, then columns 1 to 6 are dropped, making column 7 the left most column.
Before you use the Pro*FORTRAN precompiler, verify that the correct version of the compiler is installed. This section contains the following topics:
|
See Also:
|
Demonstration programs are provided to show the features of the Pro*FORTRAN precompiler. All demonstration programs are located in the $ORACLE_HOME/precomp/demo/profor directory. By default, all programs are dynamically linked with the client shared library.
To run the demonstration programs, the demonstration tables created by the $ORACLE_HOME/sqlplus/demo/demobld.sql script must exist in the JONES schema with a password.
|
Note: You must unlock the JONES account and set the password before creating the demonstrations. |
To create the demonstration programs, use the demo_profor.mk make file, located in the $ORACLE_HOME/precomp/demo/profor directory. For example, to precompile, compile, and link the sample1 demonstration program, run the following command:
$ make -f demo_profor.mk sample1
To create the Pro*FORTRAN demonstration programs, run the following command:
$ make -f demo_profor.mk samples
Some demonstration programs require you to run a SQL script that is located in the $ORACLE_HOME/precomp/demo/sql directory. If you do not run the script, then a message prompting you to run it is displayed.
To build a demonstration program and run the corresponding SQL script, include the make macro argument RUNSQL=run on the command line. For example, to create the sample11 demonstration program and run the required $ORACLE_HOME/precomp/demo/sql/sample11.sql script, run the following command:
$ make -f demo_profor.mk sample11 RUNSQL=run
To create the Pro*FORTRAN demonstration programs and run all the required SQL scripts, run the following command:
$ make -f demo_profor.mk samples RUNSQL=run
You can use the $ORACLE_HOME/precomp/demo/profor/demo_profor.mk make file to create user programs. This make file builds either 32-bit or 64-bit user programs. You can also use the demo_profor_32.mk make file to build 32-bit user programs. The following table shows the make files that you can use to build 32-bit and 64-bit user programs with Pro*FORTRAN:
| Platform | 64-bit Make File | 32-Bit Make File |
|---|---|---|
| AIX, HP-UX, and Solaris | demo_profor.mk | demo_profor_32.mk |
|
See Also: The make file for more information about creating user programs |
To create a program using the demo_proc.mk make file, run a command similar to the following:
$ make -f demo_profor.mk target FORS="forfile1 forfile2 ..." EXE=exename
In this example:
target is the make file target that you want to use
forfilen is the FORTRAN source for the program
exename is the executable program
For example, to create the program myprog from the Pro*FORTRAN source file myprog.pfo, run one of the following commands, depending on the type of executable that you want to create:
For an executable dynamically linked with the client shared library, run the following command:
$ make -f demo_profor.mk build FORS=myprog.f EXE=myprog
For an executable statically linked with the client shared library, run the following command:
$ make -f demo_profor.mk build_static FORS=myprog.f EXE=myprog
|
Note: The information in this section applies to the AIX platform. |
Before using SQL*Module for Ada, verify that the correct version of the compiler is installed.
|
See Also:
|
This section contains the following topics:
Demonstration programs are provided to show the features of SQL*Module for Ada. All demonstration programs are located in the $ORACLE_HOME/precomp/demo/modada directory. By default, all programs are dynamically linked with the client shared library.
To run the ch1_drv demonstration program, the demonstration tables created by the $ORACLE_HOME/sqlplus/demo/demobld.sql script must exist in the JONES schema with a password.
|
Note: You must unlock the JONES account and set the password before creating the demonstrations. |
The demcalsp and demohost demonstration programs require that the sample college database exists in the MODTEST schema. You can use the appropriate make command to create the MODTEST schema and load the sample college database.
Run the following command to create the SQL*Module for Ada demonstration programs, run the necessary SQL scripts to create the MODTEST user, and create the sample college database:
$ make -f demo_modada.mk all RUNSQL=run
To create a single demonstration program (demohost) and run the necessary SQL scripts to create the MODTEST user, and create the sample college database, run the following command:
$ make -f demo_modada.mk makeuser loaddb demohost RUNSQL=run
To create the SQL*Module for Ada demonstration programs, without re-creating the sample college database, run the following command:
$ make -f demo_modada.mk samples
To create a single demonstration program (demohost), without re-creating the sample college database, run the following command:
$ make -f demo_modada.mk demohost
To run the programs, you must define an Oracle Net connect string or alias named INST1_ALIAS that is used to connect to the database where the appropriate tables exist.
You can use the $ORACLE_HOME/precomp/demo/modada/demo_modada.mk make file to create user programs. To create a user program with the demo_modada.mk make file, run a command similar to the following:
$ make -f demo_modada.mk ada OBJS="module1 module2 ..." \ EXE=exename MODARGS=SQL_Module_arguments
In this example:
modulen is a compiled Ada object
exename is the executable program
SQL_Module_arguments are the command-line arguments to be passed to the SQL*Module
Before you use the Oracle Call Interface (OCI) or Oracle C++ Call Interface (OCCI), verify that the correct version of C or C++ is installed.
|
See Also:
|
This section contains the following topics:
Demonstration programs that show the features of OCI and OCCI are provided with the software through the Oracle Database 11g Examples media. There are two types of demonstration programs: C and C++. All demonstration programs are located in the $ORACLE_HOME/rdbms/demo directory. By default, all programs are dynamically linked with the client shared library.
To run the demonstration programs, the programs require the demonstration tables created by the $ORACLE_HOME/sqlplus/demo/demobld.sql script to exist in the JONES schema with a password. Some demonstration programs require specific .sql files to be run, as mentioned in the demonstration source files. OCCI demonstration programs require occidemo.sql to be run.
|
Note: You must unlock the JONES account and set the password before creating the demonstrations. |
Use the demo_rdbms.mk make file, which is located in the $ORACLE_HOME/rdbms/demo directory, to create the demonstration programs. For example, to compile and link the cdemo1 demonstration program, run the following command:
$ make -f demo_rdbms.mk cdemo1
To create the C demonstration programs for OCI, run the following command:
$ make -f demo_rdbms.mk demos
To create the C++ demonstration programs for OCCI, run the following command:
$ make -f demo_rdbms.mk occidemos
You can use the $ORACLE_HOME/rdbms/demo/demo_rdbms.mk make file to build user programs. This make file builds either 32-bit or 64-bit user programs. You can also use the demo_rdbms32.mk to build 32-bit user programs on a 64-bit operating system. The following table shows the make files that you can use to build 32-bit and 64-bit user programs with Pro*FORTRAN:
| Platform | 64-bit Make File | 32-Bit Make File |
|---|---|---|
| AIX, HP-UX, Solaris, and Linux x86-64 | demo_rdbms.mk | demo_rdbms32.mk |
| Linux x86 | NA | demo_rdbms.mk |
|
See Also: The make file for more information about building user programs |
|
Note:
|
To run JDBC/OCI demonstration programs with a 64-bit driver:
Add $ORACLE_HOME/jdbc/lib/ojdbc5.jar to the start of the CLASSPATH environment variable value for each of the following files:
jdbc/demo/samples/jdbcoci/Makefile jdbc/demo/samples/generic/Inheritance/Inheritance1/Makefile jdbc/demo/samples/generic/Inheritance/Inheritance2/Makefile jdbc/demo/samples/generic/Inheritance/Inheritance3/Makefile jdbc/demo/samples/generic/JavaObject1/Makefile jdbc/demo/samples/generic/NestedCollection/Makefile
In the $ORACLE_HOME/jdbc/demo/samples/generic/Makefile file, modify the JAVA and JAVAC variables to specify the JDK location and the -d64 flag as follows:
JAVA=${ORACLE_HOME}/java/bin/java -d64
JAVAC=${ORACLE_HOME}/java/bin/javac -d64
Set the LD_LIBRARY_PATH_64 environment variable to include the $ORACLE_HOME/lib directory.
|
Note: On AIX, theLIBPATH variable is the LD_LIBRARY_PATH_64 variable equivalent. You must use the LIBPATH variable on AIX instead of the LD_LIBRARY_PATH_64 variable. |
Oracle recommends that you use the demo_product.mk make files provided with the software to create user programs as described in the product-specific sections of this chapter. If you modify the provided make file or if you choose to use a custom-written make file, then remember that the following restrictions apply:
Do not modify the order of the Oracle libraries. Oracle libraries are included on the link line more than once so that all the symbols are resolved during linking.
Except for AIX, the order of the Oracle libraries is essential on all platforms for the following reasons:
Oracle libraries are mutually referential. For example, functions in library A call functions in library B, and functions in library B call functions in library A.
The HP-UX linkers are one-pass linkers. The AIX, Linux, and Solaris linkers are two-pass linkers.
Add the library to the beginning or to the end of the link line. Do not place user libraries between the Oracle libraries.
If you choose to use a make utility such as nmake or GNU make, then you must be aware of how macro and suffix processing differs from the make utility provided with the operating system. Oracle make files are tested and supported with the make utility.
Oracle library names and the contents of Oracle libraries are subject to change between releases. Always use the demo_product.mk make file that ships with the current release as a guide to determine the required libraries.
Oracle provides the symfind utility to assist you in locating a library or object file where a symbol is defined. When linking a program, undefined symbols are a common error that produce an error message similar to the following:
$ make -f demo_proc.mk sample1 Undefined first referenced symbol in file sqlcex sample1.o sqlglm sample1.o ld: irrecoverable: Symbol referencing errors. No output written to sample1
The error occurs when the linker cannot find a definition for a referenced symbol. If this error message is displayed, then verify that the library or object file containing the definition exists on the link line and that the linker is searching the correct directories for the file.
The following example shows the output from the symfind utility, which is used to locate the sqlcex symbol:
$ symfind sqlcex
SymFind - Find Symbol <sqlcex> in <**>.a, .o, .so
------------------------------------------------------
Command: /u01/app/oracle/product/11.2.0/bin/symfind sqlcex
Local Directory: /u01/app/oracle/product/11.2.0
Output File: (none)
Note: I do not traverse symbolic links
Use '-v' option to show any symbolic links
Locating Archive and Object files ...
[11645] | 467572| 44|FUNC |GLOB |0 |8 |sqlcex
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ./lib/libclntsh.sl
[35] | 0| 44|FUNC |GLOB |0 |5 |sqlcex
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ./lib/libsql.a
The Oracle libraries provided with this release are thread-safe, they support multithreaded applications.
Oracle Database uses signals for two-task communication. Signals are installed in a user process when the process connects to the database and are removed when it disconnects.
Table 6-5 describes the signals that Oracle Database uses for two-task communication.
Table 6-5 Signals for Two-Task Communication
| Signal | Description |
|---|---|
|
The pipe driver uses SIGCLD, also referred to as SIGCHLD, when an Oracle process terminates. The operating system kernel sends a SIGCLD signal to the user process. The signal handler uses the | |
|
The pipe two-task driver uses SIGCONT to send out-of-band breaks from the user process to the Oracle process. | |
|
Two-task drivers use SIGINT to detect user interrupt requests. The Oracle process does not catch SIGINT; the user process catches it. | |
|
Oracle Net protocols use SIGIO to indicate incoming networking events. | |
|
The pipe driver uses SIGPIPE to detect end-of-file on the communications channel. When writing to the pipe, if no reading process exists, then a SIGPIPE signal is sent to the writing process. Both the Oracle process and the user process catch SIGPIPE. SIGCLD is similar to SIGPIPE, but it applies only to user processes, not to Oracle processes. | |
|
The pipe driver uses SIGTERM to signal interrupts from the user to the Oracle process. This occurs when the user presses the interrupt key, Ctrl+C. The user process does not catch SIGTERM; the Oracle process catches it. | |
|
Oracle Net TCP/IP drivers use SIGURG to send out-of-band breaks from the user process to the Oracle process. |
The listed signals affect all precompiler applications. You can install one signal handler for SIGCLD (or SIGCHLD) and SIGPIPE when connected to the Oracle process. If you call the osnsui() routine to set it up, then you can have multiple signal handles for SIGINT. For SIGINT, use osnsui() and osncui() to register and delete signal-catching routines.
You can also install as many signal handlers as you want for other signals. If you are not connected to the Oracle process, then you can have multiple signal handlers.
Example 6-1 shows how to set up a signal routine and a catching routine.
Example 6-1 Signal Routine and Catching Routine
/* user side interrupt set */ word osnsui( /*_ word *handlp, void (*astp), char * ctx, _*/) /* ** osnsui: Operating System dependent Network Set User-side Interrupt. Add an ** interrupt handling procedure astp. Whenever a user interrupt(such as a ^C) ** occurs, call astp with argument ctx. Put in *handlp handle for this ** handler so that it may be cleared with osncui. Note that there may be many ** handlers; each should be cleared using osncui. An error code is returned if ** an error occurs. */ /* user side interrupt clear */ word osncui( /*_ word handle _*/ ); /* ** osncui: Operating System dependent Clear User-side Interrupt. Clear the ** specified handler. The argument is the handle obtained from osnsui. An error ** code is returned if an error occurs. */
Example 6-2 shows how to use the osnsui() and the osncui() routines in an application program.
Example 6-2 osnsui() and osncui() Routine Template
/*
** User interrupt handler template.
*/
void sig_handler()
{
...
}
main(argc, argv)
int arc;
char **argv;
{
int handle, err;
...
/* Set up the user interrupt handler */
if (err = osnsui(&handle, sig_handler, (char *) 0))
{
/* If the return value is nonzero, then an error has occurred
Take appropriate action for the error. */
...
}
...
/* Clear the interrupt handler */
if (err = osncui(handle))
{
/* If the return value is nonzero, then an error has occurred
Take appropriate action for the error. */
...
}
...
}
Oracle XA is the Oracle implementation of the X/Open Distributed Transaction Processing XA interface. The XA standard specifies a bidirectional interface between resource managers that provide access to shared resources within transactions, and between a transaction service that monitors and resolves transactions.
Oracle Call Interface has XA functionality. When building a TP-monitor XA application, ensure that the TP-monitor libraries (that define the symbols ax_reg and ax_unreg) are placed in the link line before the Oracle client shared library. This link restriction is required when using the XA dynamic registration (Oracle XA switch xaoswd).
Oracle Database XA calls are defined in both the client shared library (libclntsh.a, libclntsh.sl, libclntsh.so, or libclntsh.dylib depending on the platform) and the client static library (libclntst11.a). These libraries are located in the $ORACLE_HOME/lib directory.
This appendix contains information about administering Oracle Database on AIX. It includes the following topics:
Memory contention occurs when processes require more memory than is available. To cope with the shortage, the system pages programs and data between memory and disks.
This section contains the following topics:
Excessive paging activity decreases performance substantially. This can become a problem with database files created on journaled file systems (JFS and JFS2). In this situation, a large number of SGA data buffers may also have analogous file system buffers containing the most frequently referenced data. The behavior of the AIX file buffer cache manager can have a significant impact on performance. It can cause an Input-Output bottleneck, resulting in lower overall system throughput.
It is possible to tune buffer-cache paging activity, but you must do it carefully and infrequently. Use the /usr/sbin/vmo command to tune the AIX system parameters in the following table:
|
See Also: AIX 5L Performance Management Guide for more information about AIX system parameters |
The purpose of the AIX file buffer cache is to reduce disk access frequency when journaled file systems are used. If this cache is too small, then disk usage increases and potentially saturates one or more disks. If the cache is too large, then memory is wasted.
You can configure the AIX file buffer cache by adjusting the minperm and maxperm parameters. In general, if the buffer hit ratio is low (less than 90 percent), as determined by the sar -b command, then increasing the minperm parameter value may help. If maintaining a high buffer hit ratio is not critical, then decreasing the minperm parameter value increases the physical memory available. Refer to the AIX documentation for more information about increasing the size of the AIX file buffer cache.
The performance gain cannot be quantified easily, because it depends on the degree of multiprogramming and the Input-Output characteristics of the workload.
Tuning the minperm and maxperm Parameters
AIX provides a mechanism for you to loosely control the ratio of page frames used for files rather than those used for computational (working or program text) segments by adjusting the minperm and maxperm values according to the following guidelines:
If the percentage of real memory occupied by file pages falls lower than the minperm value, then the virtual memory manager (VMM) page-replacement algorithm takes both file and computational pages, regardless of repage rates.
If the percentage of real memory occupied by file pages rises above the maxperm value, then the VMM page-replacement algorithm takes both file and computational pages.
If the percentage of real memory occupied by file pages is between the minperm and maxperm parameter values, then the VMM normally takes only file pages. However, if the repaging rate for file pages is higher than the repaging rate for computational pages, then the computational pages are taken as well.
Use the following algorithm to calculate the default values:
minperm (in pages) = ((number of page frames)-1024) * 0.2
maxperm (in pages) = ((number of page frames)-1024) * 0.8
Use the following command to change the value of the minperm parameter to 5 percent of the total number of page frames, and the value of the maxperm parameter to 20 percent of the total number of page frames:
# /usr/sbin/vmo -o minperm percent=5 -o maxperm percent=20
The default values are 20 percent and 80 percent, respectively.
To optimize for quick response when opening new database connections, adjust the minfree parameter to maintain enough free pages in the system to load the application into memory without adding additional pages to the free list. To determine the real memory size (resident set size, working set) of a process, use the following command:
$ ps v process_id
Set the minfree parameter to this value or to 8 frames, whichever is larger.
If you are using Direct Input-Output, then you can set the minperm and maxperm parameters to low values. For example, 5 percent and 20 percent, respectively. This is because the AIX file buffer cache is not used for Direct Input-Output. The memory may be better used for other purposes, such as for the Oracle System Global Area.
Inadequate paging space (swap space) usually causes the system to stop responding or show very slow response times. On AIX, you can dynamically add paging space on raw disk partitions. The amount of paging space you should configure depends on the amount of physical memory present and the paging space requirements of the applications. Use the lsps command to monitor paging space use and the vmstat command to monitor system paging activities. To increase the paging space, use the smit pgsp command.
If paging space is preallocated, then Oracle recommends that you set the paging space to a value larger than the amount of RAM. But on AIX, paging space is not allocated until required. The system uses swap space only if it runs out of real memory. If the memory is sized correctly, then there is no paging and the page space can be small. Workloads where the demand for pages does not fluctuate significantly perform well with a small paging space. Workloads likely to have peak periods of increased paging require enough paging space to handle the peak number of pages.
As a general rule, an initial setting for the paging space is half the size of RAM plus 4 GB, with an upper limit of 32 GB. Monitor the paging space use with the lsps -a command, and increase or decrease the paging space size accordingly. The metric percent Used in the output of lsps -a is typically less than 25 percent on a healthy system. A properly sized deployment requires very little paging space and an excessive amount of swapping is an indication that the RAM on the system may be undersized.
|
Caution: Do not undersize the paging space. If you do, then the system terminates active processes when it runs out of space. However, oversizing the paging space has little or no negative impact. |
Constant and excessive paging indicates that the real memory is over-committed. In general, you should:
Avoid constant paging unless the system is equipped with very fast expanded storage that makes paging between memory and expanded storage much faster than Oracle Database can read and write data between the SGA and disks.
Allocate limited memory resource to where it is most beneficial to system performance. It is sometimes a recursive process of balancing the memory resource requirements and trade-offs.
If memory is not adequate, then build a prioritized list of memory-requiring processes and elements of the system. Assign memory to where the performance gains are the greatest. A prioritized list may look like the following:
OS and RDBMS kernels
User and application processes
Redo log buffer
PGAs and shared pool
Database block buffer caches
For example, suppose you query Oracle Database dynamic performance tables and views and find that both the shared pool and database buffer cache require more memory. Then, assigning the limited spare memory to the shared pool may be more beneficial than assigning it to the database block buffer caches.
The following AIX commands provide paging status and statistics:
vmstat -s
vmstat interval [repeats]
sar -r interval [repeats]
You can configure Oracle Database block size for better Input-Output throughput. On AIX, you can set the value of the DB_BLOCK_SIZE initialization parameter to between 2 KB and 32 KB, with a default of 4 KB. If Oracle Database is installed on a journaled file system, then the block size should be a multiple of the file system block size (4 KB on JFS, 16 K to 1 MB on GPFS). For databases on raw partitions, Oracle Database block size is a multiple of the operating system physical block size (512 bytes on AIX).
Oracle recommends smaller Oracle Database block sizes (2 KB or 4 KB) for online transaction processing or mixed workload environments and larger block sizes (8 KB, 16 KB, or 32 KB) for decision support system workload environments.
By increasing the LOG_BUFFER size, you may be able to improve the speed of archiving the database, particularly if transactions are long or numerous. Monitor the log file Input-Output activity and system throughput to determine the optimum LOG_BUFFER size. Tune the LOG_BUFFER parameter carefully to ensure that the overall performance of normal database activity does not degrade.
|
Note: TheLOG_ARCHIVE_BUFFER_SIZE parameter was obsoleted with Oracle8i Database. |
For high-speed data loading, such as using the SQL*Loader direct path option in addition to loading data in parallel, the CPU spends most of its time waiting for Input-Output to complete. By increasing the number of buffers, you can maximize CPU usage, and by doing this, increase overall throughput.
The number of buffers (set by the SQL*Loader BUFFERS parameter) you choose depends on the amount of available memory and how much you want to maximize CPU usage.
The performance gains depend on CPU usage and the degree of parallelism that you use when loading data.
|
See Also: Oracle Database Utilities for information about adjusting the file processing options string for theBUFFERS parameter and for information about the SQL*Loader utility |
BUFFER Parameter for the Import Utility
The BUFFER parameter for the Import utility should be set to a large value to optimize the performance of high-speed networks when they are used. For example, if you use the IBM RS/6000 Scalable POWER parallel Systems switch, then you should set the BUFFER parameter to a value of at least 1 MB.
Disk Input-Output contention can result from poor memory management (with subsequent paging and swapping), or poor distribution of tablespaces and files across disks.
Ensure that the Input-Output activity is distributed evenly across multiple disk drives by using AIX utilities such as filemon, sar, iostat, and other performance tools to identify disks with high Input-Output activity.
This section contains the following topics:
The AIX Logical Volume Manager can stripe data across multiple disks to reduce disk contention. The primary objective of striping is to achieve high performance when reading and writing large sequential files. Effective use of the striping features in the Logical Volume Manager enables you to spread Input-Output more evenly across disks, resulting in better overall performance.
|
Note: Do not add logical volumes to Automatic Storage Management disk groups. Automatic Storage Management works best when you add raw disk devices to disk groups. If you are using Automatic Storage Management, then do not use Logical Volume Manager for striping. Automatic Storage Management implements striping and mirroring. |
Design a Striped Logical Volume
When you define a striped logical volume, you must specify the items listed in the following table:
| Item | Recommended Settings |
|---|---|
| Drives | There must be at least two physical drives. The drives should have minimal activity when performance-critical sequential Input-Output is carried out. Sometimes, you must stripe the logical volume between two or more adapters. |
| Stripe unit size | Although the stripe unit size can be any power of 2 (from 2 KB to 128 KB), stripe sizes of 32 KB and 64 KB are good values for most workloads. For Oracle Database files, the stripe size must be a multiple of the database block size. |
| Size | The number of physical partitions allocated to the logical volume must be a multiple of the number of disk drives used. |
| Attributes | Cannot be mirrored. Set the copies attribute to a value of 1. |
Other Considerations
Performance gains from effective use of the Logical Volume Manager can vary greatly, depending on the Logical Volume Manager you use and the characteristics of the workload. For decision support system workloads, you can see substantial improvement. For online transaction processing-type or mixed workloads, you can expect significant performance gains.
Address the following considerations when deciding whether to use journaled file systems or raw logical volumes:
File systems are continually being improved, as are various file system implementations.
File systems require some additional configuration (AIX minservers and maxservers parameter) and add a small CPU overhead because Asynchronous Input-Output on file systems is serviced outside the kernel.
Different vendors implement the file system layer in different ways to capitalize on the strengths of different disks. This makes it difficult to compare file systems across platforms.
The introduction of more powerful Logical Volume Manager interfaces substantially reduces the tasks of configuring and backing up logical disks based on raw logical volumes.
The Direct Input-Output and Concurrent Input-Output features included in IBM AIX on POWER Systems improve file system performance to a level comparable to raw logical volumes.
In earlier versions of AIX, file systems supported only buffered read and write and added extra contention because of imperfect inode locking. These two issues are solved by the JFS2 Concurrent Input-Output feature and the GPFS Direct Input-Output feature.
|
Note: To use the Oracle RAC option, you must place data files on an Automatic Storage Management disk group or on a GPFS file system. You cannot use JFS or JFS2. Direct Input-Output is implicitly enabled when you use GPFS. |
IBM AIX on POWER Systems includes Direct Input-Output and Concurrent Input-Output support. Direct Input-Output and Concurrent Input-Output support enables database files to exist on file systems while bypassing the operating system buffer cache and removing inode locking operations that are redundant with the features provided by Oracle Database.
Where possible, Oracle recommends enabling Concurrent Input-Output or Direct Input-Output on file systems containing Oracle data files. The following table lists file systems available on AIX and the recommended setting:
| File System | Option | Description |
|---|---|---|
| JFS | dio | Concurrent Input-Output is not available on JFS. Direct Input-Output is available, but performance is degraded compared to JFS2 with Concurrent Input-Output. |
| JFS large file | none | Oracle does not recommend using JFS large file for Oracle Database because its 128 KB alignment constraint prevents you from using Direct Input-Output. |
| JFS2 | cio | Concurrent Input-Output is a better setting than Direct Input-Output on JFS2, because it provides support for multiple concurrent readers and writers on the same file. However, due to AIX restrictions on JFS2/CIO, Concurrent Input-Output is intended to be used only with Oracle data files, control files, and log files. It should be applied only to file systems that are dedicated to such a purpose. For the same reason, the Oracle home directory is not supported on a JFS2 file system mounted with the cio option. For example, during installation, if you inadvertently specify that the Oracle home directory is on a JFS2 file system mounted with the CIO option, then while trying to relink Oracle, you may encounter the following error:
|
| GPFS | NA | Oracle Database silently enables Direct Input-Output on GPFS for optimum performance. GPFS Direct Input-Output supports multiple readers and writers on multiple nodes. Therefore, Direct Input-Output and Concurrent Input-Output are the same thing on GPFS. |
Considerations for JFS and JFS2
If you are placing Oracle Database logs on a JFS2 file system, then the optimal configuration is to create the file system using the agblksize=512 option and to mount it with the cio option.
Before Oracle Database 11g, Direct Input-Output and Concurrent Input-Output could not be enabled at the file level on JFS/JFS2. Therefore, the Oracle home directory and data files had to be placed in separate file systems for optimal performance. The Oracle home directory was placed on a file system mounted with default options, with the data files and logs on file systems mounted using the dio or cio options.
With Oracle Database 11g, you can enable Direct Input-Output and Concurrent Input-Output on JFS/JFS2 at the file level. You can do this by setting the FILESYSTEMIO_OPTIONS parameter in the server parameter file to setall or directIO. This enables Concurrent Input-Output on JFS2 and Direct Input-Output on JFS for all data file Input-Output. Because the directIO setting disables asynchronous Input-Output it should normally not be used. As a result of this 11g feature, you can place data files on the same JFS/JFS2 file system as the Oracle home directory and still use Direct Input-Output or Concurrent Input-Output for improved performance. As mentioned earlier, you should still place Oracle Database logs on a separate JFS2 file system for optimal performance.
If you are using GPFS, then you can use the same file system for all purposes. This includes using it for the Oracle home directory and for storing data files and logs. For optimal performance, you should use a large GPFS block size (typically, at least 512 KB). GPFS is designed for scalability, and there is no requirement to create multiple GPFS file systems as long as the amount of data fits in a single GPF¢y]†S file system.
Moving from a Journaled File System to Raw Logical Volumes
To move from a journaled file system to raw devices without having to manually reload all the data, perform the following steps as the root user:
Create a raw device (preferably, in a BigVG) using the new raw logical volume device type (-T O), which enables putting the first Oracle block at offset zero for optimal performance:
# mklv -T O -y new_raw_device VolumeGroup NumberOfPartitions
|
Note: The raw device should be larger than the existing file. In addition, you must bear in mind the size of the new raw device to prevent wasting space. |
Set the permissions on the raw device.
Use dd to convert and copy the contents of the JFS file to the new raw device as follows:
# dd if=old_JFS_file of=new_raw_device bs=1m
Rename the data file.
Moving from Raw Logical Volumes to a Journaled File System
The first Oracle block on a raw logical volume is not necessarily at offset zero. However, the first Oracle block on a file system is always at offset zero. To determine the offset and locate the first block on a raw logical volume, use the $ORACLE_HOME/bin/offset command. The offset can be 4096 bytes or 128 KB on AIX logical volumes or zero on AIX logical volumes created with the mklv -T O option.
When you have determined the offset, you can copy over data from a raw logical volume to a file system using the dd command and skipping the offset. The following example assumes an offset of 4096 bytes:
# dd if=old_raw_device bs=4k skip=1|dd of=new_file bs=256
You can instruct Oracle Database to use many blocks smaller than the maximum capacity of a raw logical volume. If you do this, then you must add a count clause to ensure that only data that contains Oracle blocks is copied. The following example assumes an offset of 4096 bytes, an Oracle block size of 8 KB, and 150000 blocks:
# dd if=old_raw_device bs=4k skip=1|dd bs=8k count=150000|dd of=new_file bs=256k
Oracle Database takes full advantage of asynchronous Input-Output provided by AIX, resulting in faster database access.
IBM AIX on POWER Systems support asynchronous Input-Output for database files created on file system partitions. When using asynchronous Input-Output on file systems, the kernel database processes (aioserver) control each request from the time a request is taken off the queue to the time it is completed. The number of aioserver servers determines the number of asynchronous Input-Output requests that can be processed in the system concurrently. So, it is important to tune the number of aioserver processes when using file systems to store Oracle Database data files.
Use one of the following commands to set the number of servers. This applies only when using asynchronous Input-Output on file systems:
smit aio
chdev -l aio0 -a maxservers=' m ' -a minservers='n'
|
See Also:
|
|
Note: On IBM AIX on POWER Systems, there are two asynchronous Input-Output subsystems available. Oracle Database 11g uses Legacy asynchronous Input-Output (aio0), even though the Oracle preinstallation script enables Legacy asynchronous Input-Output (aio0) and POSIX AIO (posix_aio0). Both asynchronous Input-Output subsystems have the same performance characteristics. |
Set the minimum value to the number of servers to be started when the system is started. Set the maximum value to the number of servers that can be started in response to a large number of concurrent requests. These parameters apply to file systems only.
The default value for the minimum number of servers is 1. The default value for the maximum number of servers is 10. These values are usually too low to run Oracle Database on large systems with 4 CPUs or more, if you are not using kernelized asynchronous Input-Output. Oracle recommends that you set the parameters to the values listed in the following table:
| Parameter | Value |
|---|---|
minservers | Oracle recommends an initial value equal to the number of CPUs on the system or 10, whichever is lower. |
maxservers | Starting with AIX 5L version 5.3, this parameter counts the maximum number of asynchronous Input-Output servers for each CPU. On previous versions of AIX, it was a systemwide value. If you are using General Parallel File System (GPFS), then set maxservers to worker1threads divided by the number of CPUs. This is the optimal setting. Increasing maxservers does not lead to improved Input-Output performance.
If you are using JFS/JFS2, then set the initial value to 10 times the number of logical disks divided by the number of CPUs. Monitor the actual number of |
maxreqs | Set the initial value to 4 times the number of logical disks multiplied by the queue depth. You can determine the queue depth by running the following command:
$ lsattr -E -l hdiskxx
Typically, the queue depth is 3. |
If the value of the maxservers or maxreqs parameter is set too low, then the following warning messages are repeatedly displayed:
Warning: lio_listio returned EAGAINPerformance degradation may be seen.
You can avoid these errors by increasing the value of the maxservers parameter. To display the number of asynchronous Input-Output servers running, enter the following commands as the root user:
# pstat -a | grep -c aios # ps -k | grep aioserver
Check the number of active asynchronous Input-Output servers periodically, and change the values of the minservers and maxservers parameters if required. The changes take place when the system is restarted.
Input-Output Slaves are specialized Oracle processes that perform only Input-Output. They are rarely used on AIX, because asynchronous Input-Output is the default and recommended way for Oracle to perform Input-Output operations on AIX. Input-Output Slaves are allocated from shared memory buffers. Input-Output Slaves use the initialization parameters listed in the following table:
| Parameter | Range of Values | Default Value |
|---|---|---|
DISK_ASYNCH_IO | true/false | true |
TAPE_ASYNCH_IO | true/false | true |
BACKUP_TAPE_IO_SLAVES | true/false | false |
DBWR_IO_SLAVES | 0 - 999 | 0 |
DB_WRITER_PROCESSES | 1-20 | 1 |
Generally, you do not adjust the parameters in the preceding table. However, on large workloads, the database writer may become a bottleneck. If it does, then increase the value of DB_WRITER_PROCESSES. As a general rule, do not increase the number of database writer processes above one for each pair of CPUs in the system or partition.
There are times when you must turn off asynchronous I/O. For example, if instructed to do so by Oracle Support for debugging. You can use the DISK_ASYNCH_IO and TAPE_ASYNCH_IO parameters to switch off asynchronous I/O for disk or tape devices. TAPE_ASYNCH_IO support is only available when the Media Manager software supports it and for Recovery Manager, if BACKUP_TAPE_IO_SLAVES is true.
Set the DBWR_IO_SLAVES parameter to greater than 0 only if the DISK_ASYNCH_IO parameter is set to false. Otherwise, the database writer process becomes a bottleneck. In this case, the optimal value on AIX for the DBWR_IO_SLAVES parameter is 4.
When using Direct Input-Output or Concurrent Input-Output with Oracle Database 11g, the AIX file system does not perform any read-ahead on sequential scans. For this reason the DB_FILE_MULTIBLOCK_READ_COUNT value in the server parameter file should be increased when Direct Input-Output or Concurrent Input-Output is enabled on Oracle data files. The read ahead is performed by Oracle Database as specified by the DB_FILE_MULTIBLOCK_READ_COUNT initialization parameter.
Setting a large value for the DB_FILE_MULTIBLOCK_READ_COUNT initialization parameter usually yields better Input-Output throughput on sequential scans. On AIX, this parameter ranges from 1 to 512, but using a value higher than 16 usually does not provide additional performance gain.
Set this parameter so that its value when multiplied by the value of the DB_BLOCK_SIZE parameter produces a number larger than the Logical Volume Manager stripe size. Such a setting causes more disks to be used.
The write behind feature enables the operating system to group write Input-Output together, up to the size of a partition. You can improve performance by doing this, because the number of Input-Output operations is reduced. The file system divides each file into 16 KB partitions to increase write performance, limit the number of dirty pages in memory, and minimize disk fragmentation. The pages of a particular partition are not written to disk until the program writes the first byte of the next 16 KB partition. To set the size of the buffer for write behind to eight 16 KB partitions, enter the following command:
à # /usr/sbin/vmo -o numclust=8
To disable write behind, enter the following command:
à # /usr/sbin/vmo -o numclust=0
|
Note: The information in this section applies only to file systems, and only when neither Direct Input-Output nor Concurrent Input-Output are used. |
The VMM anticipates the need for pages of a sequential file. It observes the pattern in which a process accesses a file. When the process accesses two consecutive pages of the file, the VMM assumes that the program continues to access the file sequentially, and schedules additional sequential reads of the file. These reads overlap the program processing and make data available to the program faster. The following VMM thresholds, implemented as kernel parameters, determine the number of pages it reads ahead:
minpgahead
This parameter stores the number of pages read ahead when the VMM first detects the sequential access pattern.
maxpgahead
This parameter stores the maximum number of pages that VMM reads ahead in a sequential file.
Set the minpgahead and maxpgahead parameters to appropriate values for an application. The default values are 2 and 8 respectively. Use the /usr/sbin/vmo command to change these values. You can use higher values for the maxpgahead parameter in systems where the sequential performance of striped logical volumes is of paramount importance. To set the minpgahead parameter to 32 pages and the maxpgahead parameter to 64 pages, run the following command as the root user:
-o minpgahead=32 -o maxpgahead=64
Set both the minpgahead and maxpgahead parameters to a power of two. For example, 2, 4, 8, . . . 512, 1042, . . . and so on.
Disk Input-Output pacing is an AIX mechanism that enables the system administrator to limit the number of pending Input-Output requests to a file. This prevents disk Input-Output intensive processes from saturating the CPU. Therefore, the response time of interactive and CPU-intensive processes does not deteriorate.
You can achieve disk Input-Output pacing by adjusting two system parameters: the high-water mark and the low-water mark. When a process writes to a file that has a pending high-water mark Input-Output request, the process is put to sleep. The process wakes up when the number of outstanding Input-Output requests falls lower than or equals the low-water mark.
You can use the smit command to change the high and low-water marks. Determine the water marks through trial-and-error. Use caution when setting the water marks, because they affect performance. Tuning the high and low-water marks has less effect on disk Input-Output larger than 4 KB.
You can determine disk Input-Output saturation by analyzing the result of iostat, in particular, the percentage of iowait and tm_act. A high iowait percentage combined with high tm_act percentages on specific disks is an indication of disk saturation.
|
Note: A highiowait alone is not necessarily an indication of an Input-Output bottleneck. |
If you disable mirror write consistency for an Oracle data file allocated on a raw logical volume, then the Oracle Database fail recovery process uses resilvering to recover after a system failure. This resilvering process prevents database inconsistencies or corruption.
During fail recovery, if a data file is allocated on a logical volume with multiple copies, then the resilvering process performs a checksum on the data blocks of all the copies. It then performs one of the following:
If the data blocks in a copy have valid checksums, then the resilvering process uses that copy to update the copies that have invalid checksums.
If all copies have blocks with invalid checksums, then the resilvering process rebuilds the blocks using information from the redo log file. It then writes the data file to the logical volume and updates all the copies.
On AIX, the resilvering process works only for data files allocated on raw logical volumes for which minor write consistency is disabled. Resilvering is not required for data files on mirrored logical volumes with minor write consistency enabled, because minor write consistency ensures that all copies are synchronized.
If the system fails while you are upgrading an earlier release of Oracle Database that used data files on logical volumes for which minor write consistency was disabled, then run the syncvg command to synchronize the mirrored logical volume before starting Oracle Database. If you do not synchronize the mirrored logical volume before starting the database, then Oracle Database may read incorrect data from an logical volume copy.
|
Note: If a disk drive fails, then resilvering does not occur. You must run thesyncvg command before you can reactivate the logical volume. |
|
Caution: Oracle supports resilvering for data files only. Do not disable minor write consistency for redo log files. |
The CPU is another system component for which processes may contend. Although the AIX kernel allocates CPU effectively most of the time, many processes compete for CPU cycles. If the system has multiple CPU (SMP), then there may be different levels of contention on each CPU.
The following sections provide information about CPU scheduling and process priorities:
The default value for the run-time slice of the AIX RR dispatcher is ten milliseconds (msec). Use the schedo command to change the time slice. A longer time slice causes a lower context switch rate if the average voluntary switch rate of the applications is lower. As a result, fewer CPU cycles are spent on context-switching for a process and the system throughput should improve.
However, a longer run-time slice can deteriorate response time, especially on a uniprocessor system. The default run-time slice is usually acceptable for most applications. When the run queue is high and most of the applications and Oracle shadow processes are capable of running a much longer duration, you may want to increase the time slice by entering the following command:
f # /usr/sbin/schedo -t n
In the preceding command, setting n to 0 results in a slice of 10 msec, choosing a value of 1 results in a slice of 20 msec, choosing a value of 2 results in a slice of 30 msec, and so on.
Binding certain processes to a processor can improve performance substantially on an SMP system. Processor binding is available and fully functional on AIX 5L.
However, starting with AIX 5L, specific improvements in the AIX scheduler enables Oracle Database processes to be scheduled optimally without processor binding. Therefore, Oracle no longer recommends binding processes to processors when running on AIX 5L version 5.3 or later.
Threads in AIX can run with process-wide contention scope (M:N) or with systemwide contention scope (1:1). The AIXTHREAD_SCOPE environment variable controls which contention scope is used.
The default value of the AIXTHREAD_SCOPE environment variable is P, which specifies process-wide contention scope. When using process-wide contention scope, Oracle threads are mapped to a pool of kernel threads. When Oracle is waiting on an event and its thread is swapped out, it may return on a different kernel thread with a different thread ID. Oracle uses the thread ID to post waiting processes, so it is important for the thread ID to remain the same. When using systemwide contention scope, Oracle threads are mapped to kernel threads statically, one to one. For this reason, Oracle recommends that you use systemwide contention. The use of systemwide contention is especially critical for Oracle Real Application Clusters (Oracle RAC) instances.
In addition, on AIX 5L version 5.3 or later, if you set systemwide contention scope, then significantly less memory is allocated to each Oracle process.
Oracle recommends that you set the value of the AIXTHREAD_SCOPE environment variable to S in the environment script that you use to set the ORACLE_HOME or ORACLE_SID environment variables for an Oracle Database instance or an Oracle Net listener process as follows:
Bourne, Bash, or Korn shell:
Add the following line to the ~/.profile or /usr/local/bin/oraenv script:
AIXTHREAD_SCOPE=S; export AIXTHREAD_SCOPE
C shell:
Add the following line to the ~/.login or /usr/local/bin/coraenv script:
setenv AIXTHREAD_SCOPE S
Doing this enables systemwide thread scope for running all Oracle processes.
Network Information Service external naming adapter is supported on AIX. To configure and use Network Information Service external naming, refer to the "Configuring External Naming Methods" section of Oracle Database Net Services Administrator's Guide.
If Simultaneous Multithreading is enabled, and AIX 5.3 and later version operating system is used, then the v$osstat view reports 2 additional rows corresponding to the online logical (NUM_LCPUS) and virtual cpus (NUM_VCPUS).
If Oracle is run on AIX 5.3 and later versions without Simultaneous Multithreading, then these rows are not reported.
If you want to configure SSL on IBM JDK, then you may face the following issues:
IBM JSSE does not support SSLv2Hello SSL protocol
For SSL clients using Thin JDBC connectors, you must set oracle.net.ss1_version system property to select TLSv1 SSL protocol or SSLv3 SSL protocol
IBM JSSE does not allow anonymous ciphers
For SSL clients using anonymous ciphers, you must replace the Default Trust Manager with a Custom Trust Manager that accepts anonymous ciphers.
|
See Also: IBM JSSE documentation for more information on creating and installing Custom Trust Manager |
This appendix contains information about administering Oracle Database on Solaris.
On Solaris systems, Oracle Database uses Intimate Shared Memory for shared memory segments because it shares virtual memory resources between Oracle processes. Intimate Shared Memory causes the physical memory for the entire shared memory segment to be locked automatically.
On Solaris 10 systems, dynamic/pageable Intimate Shared Memory is available. This enables Oracle Database to share virtual memory resources between processes sharing the segment, and at the same time, enables memory paging. The operating system does not have to lock down physical memory for the entire shared memory segment.
Oracle Database automatically selects Intimate Shared Memory or Dynamic Intimate Shared Memory based on the following criteria:
Oracle Database uses Dynamic Intimate Shared Memory if it is available on the system, and if the value of the SGA_MAX_SIZE initialization parameter is larger than the size required for all SGA components combined. This enables Oracle Database to lock only the amount of physical memory that is used. Oracle Database also uses DISM if it is available on the system and MEMORY_TARGET or MEMORY_MAX_TARGET is set by the user.
Oracle Database uses Intimate Shared Memory if the entire shared memory segment is in use at startup or if the value of the SGA_MAX_SIZE parameter equals or smaller than the size required for all SGA components combined.
Regardless of whether Oracle Database uses Intimate Shared Memory or Dynamic Intimate Shared Memory, it can always exchange the memory between dynamically sizable components such as the buffer cache, the shared pool, and the large pool after it starts an instance. Oracle Database can relinquish memory from one dynamic SGA component and allocate it to another component.
Because shared memory segments are not implicitly locked in memory, when using Dynamic Intimate Shared Memory, Oracle Database explicitly locks shared memory that is currently in use at startup. When a dynamic SGA operation uses more shared memory, Oracle Database explicitly performs a lock operation on the memory that is put to use. When a dynamic SGA operation releases shared memory, Oracle Database explicitly performs an unlock operation on the memory that is freed, so that it becomes available to other applications.
Oracle Database uses the oradism utility to lock and unlock shared memory. The oradism utility is automatically set up during installation. It is not required to perform any configuration tasks to use dynamic SGA.
|
Note:
|
This appendix contains information about administering Oracle Database on Linux. From Oracle
It contains the following topics:
|
Note: Starting with Oracle Database 11g release 2 (11.2), Linux x86-64 media does not contain Linux x86 binaries. You must use Linux x86 media to install 32-bit Oracle home. |
|
Note: This section applies to Linux x86 only. |
Oracle Database can allocate and use more than 4 GB of memory for the database buffer cache. This section describes the limitations and requirements of the extended buffer cache feature on Linux x86 systems.
To use the extended buffer cache feature, create an in-memory file system on the /dev/shm mount point equal in size or larger than the amount of memory that you intend to use for the database buffer cache. For example, to create an 8 GB file system on the /dev/shm mount point:
Run the following command as the root user:
# mount -t tmpfs shmfs -o size=8g /dev/shm
To ensure that the in-memory file system is mounted when the system restarts, add an entry in the /etc/fstab file similar to the following:
shmfs /dev/shm tmpfs size=8g 0 0
When Oracle Database starts with the extended buffer cache feature enabled, it creates a file in the /dev/shm directory that corresponds to the Oracle buffer cache.
|
Note: If an in-memory file system is mounted on the/dev/shm mount point, then ensure that its size equals or is larger than the amount of memory that is used for the database buffer cache. |
USE_INDIRECT_DATA_BUFFERS Initialization Parameter
To enable the extended buffer cache feature, set the USE_INDIRECT_DATA_BUFFERS initialization parameter to TRUE in the parameter file. This enables Oracle Database to specify a larger buffer cache.
If the extended cache feature is enabled, then you must use the DB_BLOCK_BUFFERS parameter to specify the database cache size.
Do not use the following dynamic cache parameters while the extended buffer cache feature is enabled:
DB_CACHE_SIZE
DB_2K_CACHE_SIZE
DB_4K_CACHE_SIZE
DB_8K_CACHE_SIZE
DB_16K_CACHE_SIZE
The following limitations apply to the extended buffer cache feature:
You cannot create or use tablespaces with nondefault block sizes. You can create tablespaces using only the block size specified by the DB_BLOCK_SIZE parameter.
You cannot change the size of the buffer cache while the instance is running.
|
See Also: Oracle Database SQL Language Reference for more information about the default block size used by theCREATE TABLESPACE command. |
|
Note: The default VLM window size is 512 MB. This memory size is allocated to the address space of the process. To increase or decrease this value, set theVLM_WINDOW_SIZE environment variable to the new size in bytes. For example, to set the VLM_WINDOW_SIZE to 256 MB, run the following command:
$ export VLM_WINDOW_SIZE=268435456 The value that you specify for the |
To enable Oracle Database to use large pages (sometimes called huge pages) on SUSE Linux Enterprise Server 10, or Red Hat Enterprise Linux 4, set the value of the vm.nr_hugepages kernel parameter to specify the number of large pages that you want to reserve. You must specify a enough large pages to hold the entire SGA for the database instance. To determine the required parameter value, divide the SGA size for the instance by the size of a large page, then round up the result to the nearest integer.
To determine the default large page size, run the following command:
# grep Hugepagesize /proc/meminfo
For example, if /proc/meminfo lists the large page size as 2 MB, and the total SGA size for the instance is 1.6 GB, then set the value for the vm.nr_hugepages kernel parameter to 820 (1.6 GB / 2 MB = 819.2).
|
See Also: Overview of HugePages for more information on tuning SGA with hugepages, configuring hugepages, and hugepages configuration restrictions. |
Oracle Database supports kernel asynchronous Input-Output. Asynchronous Input-Output is enabled by default on raw volumes. Automatic Storage Management uses asynchronous Input-Output by default.
By default, the DISK_ASYNCH_IO initialization parameter in the parameter file is set to TRUE. To enable asynchronous Input-Output on file system files:
Ensure that all Oracle Database files are located on file systems that support asynchronous Input-Output.
Set the FILESYSTEMIO_OPTIONS initialization parameter in the parameter file to ASYNCH or SETALL.
|
Note: If the file system files are managed through ODM library interface or dNFS, asynchronous Input-Output is enabled by default. There is no need to set FILESYSTEMIO_OPTIONS to enable asynchronous Input-Output in these environments. |
If Simultaneous Multithreading is enabled, then the v$osstat view reports two additional rows corresponding to the online logical (NUM_LCPUS) and virtual CPUs (NUM_VCPUS).
To use the MEMORY_TARGET or MEMORY_MAX_TARGET feature, the following kernel parameters must be potentially modified.
/dev/shm mount point should be equal in size or larger than the value of SGA_MAX_SIZE, if set, or should be set to be at least MEMORY_TARGET or MEMORY_MAX_TARGET, whichever is larger. For example, with MEMORY_MAX_TARGET=4GB only set, to create a 4GB system on the /dev/shm mount point:
Run the following command as the root user:
# mount -t tmpfs shmfs -o size=4g /dev/shm
Ensure that the in-memory file system is mounted when the system restarts, add an entry in the /etc/fstab file similar to the following:
# shmfs /dev/shm tmpfs size=4g 0
The number of file descriptors for each Oracle instance are increased by 512*PROCESSES. Therefore, the maximum number of file descriptors should be at least this value, plus some more for the operating system requirements. For example, if the cat /proc/sys/fs/file-max command returns 32768 and PROCESSES are 100, you can set it to 6815744 or higher as root, to have 51200 available for Oracle. Use one of the following options to set the value for the file-max descriptor.
Run the following command:
echo 6815744 > /proc/sys/fs/file-max
OR
Modify the following entry in the /etc/sysctl.conf file and restart the system as root.
fs.file-max = 6815744
Per-process number of file descriptors must be at least 512. For example, as root run the following command.
On bash and sh:
# ulimit -n
On csh:
# limit descriptors
If the preceding command returns 200, then run the following command to set the value for the per processor file descriptors limit, for example to 1000:
On bash and sh:
# sudo sh # ulimit -n 1000
On csh:
# sudo sh # limit descriptors 1000
MEMORY_TARGET and MEMORY_MAX_TARGET cannot be used when LOCK_SGA is enabled. MEMORY_TARGET and MEMORY_MAX_TARGET also cannot be used with huge pages on Linux.
To migrate an Oracle Database 11g Release 2 (11.2) for 32-bit Linux to an Oracle Database 11g Release 2 (11.2) for 64-bit Linux, you must perform the following steps:
Online backup enables to take a backup of the database without having to shutdown the database. To achieve this, perform the following steps:
Connect to the database instance as SYSDBA:
SQL> CONNECT / AS SYSDBA;
Run the following commands to ensure that the database is in ARCHIVELOG mode:
SQL> SHUTDOWN IMMEDIATE Database closed Database dismounted Oracle instance shutdown SQL> STARTUP MOUNT Oracle instance started Total System Global Area 272629760 bytes Fixed Size 788472 bytes Variable Size 103806984 bytes Database Buffers 167772160 bytes Redo Buffers 262144 bytes Database mounted SQL>ALTER DATABASE ARCHIVELOG; Database altered SQL> ALTER DATABASE OPEN; Database altered
Run the following command to start RMAN, which is located under $ORACLE_HOME/bin directory:
RMAN>connect target
To backup the 32-bit database and all the archived redo log files, run the following command:
RMAN>backup database plus archivelog delete input;
|
Note: Archive redo logs are very important to recover the database. Oracle recommends that you back them up along with your database. You can backup the archive redo logs from time to time by issuing the following command:RMAN>backup archivelog all delete input; |
This section covers the following topics:
Migrating 32-Bit Database to 64-Bit Database With the Same Directory Structure for Data Files
Migrating 32-Bit Database to 64-Bit Database With Different Directory Structure for Data Files
If the control file, data file, redo log files have the same structure on the target computer as in the source computer, then perform the following steps:
Perform an online backup of the database before starting the migration process. Refer to Online Backup of Database With RMAN for more information.
Install Oracle Database 11g Release 2 (11.2) for 64-bit Linux in a new Oracle Database home. It is recommended that you use the same version of Oracle Database home as on the 32-bit computer.
Copy init.ora, data files, control file, and the redo log files from the 32-bit Linux computer to the corresponding locations on the 64-bit Linux computer.
Edit init.ora file to include the following changes:
Update the memory requirements included in the file.
Edit the control file location if necessary.
|
Note: Oracle recommends that you double the values of shared pool, java pool,sga_target and large pool listed in the init.ora file. |
Connect to the database instance as SYSDBA:
SQL> CONNECT / AS SYSDBA;
Set the system to spool results to a log file for later verification of success. For example:
SQL> SPOOL /tmp/utlirp.log
Start the 64-bit Oracle Database as follows:
SQL> STARTUP UPGRADE pfile=init.ora;
Run the following command on the 64-bit Oracle Database, to invalidate all the PL/SQL modules:
SQL> @$ORACLE_HOME/rdbms/admin/utlirp.sql
Shut down the 64-bit Oracle Database:
SQL>shutdown immediate;
Start the 64-bit Oracle Database:
SQL> STARTUP pfile=init.ora;
If the JServer JAVA Virtual Machine component is installed, perform the following steps after connecting as SYS:
begin
update obj$ set status=5 where obj#=(select obj# from obj$,javasnm$
where owner#=0 and type#=29 and short(+)=name and
nvl(longdbcs,name)='oracle/aurora/rdbms/Compiler');
commit;
declare
cursor C1 is select
'DROP JAVA DATA "' || u.name || '"."' || o.name || '"'
from obj$ o,user$ u where o.type#=56 and u.user#=o.owner#;
ddl_statement varchar2(200);
iterations number;
previous_iterations number;
loop_count number;
my_err number;
begin
previous_iterations := 10000000;
loop
-- To make sure we eventually stop, pick a max number of iterations
select count(*) into iterations from obj$ where type#=56;
exit when iterations=0 or iterations >= previous_iterations;
previous_iterations := iterations;
loop_count := 0;
open C1;
loop
begin
fetch C1 into ddl_statement;
exit when C1%NOTFOUND or loop_count > iterations;
exception when others then
my_err := sqlcode;
if my_err = -1555 then -- snapshot too old, re-execute fetch query
exit;
else
raise;
end if;
end;
initjvmaux.exec(ddl_statement);
loop_count := loop_count + 1;
end loop;
close C1;
end loop;
end;
commit;
initjvmaux.drp('delete from java$policy$shared$table');
update obj$ set status=1 where obj#=(select obj# from obj$,javasnm$
where owner#=0 and type#=29 and short(+)=name and
nvl(longdbcs,name)='oracle/aurora/rdbms/Compiler');
commit;
end;
/
create or replace java system;
/
Revalidate all the existing PL/SQL modules in the format required by the 64-bit Oracle Database:
SQL>$ORACLE_HOME/rdbms/admin/utlrp.sql;
If the control file, data file, redo log files have different structure on the target computer as compared to the source computer, then perform the following steps:
Perform an online backup of the database before starting the migration process. Refer to Online Backup of Database With RMAN for more information.
Install Oracle Database 11g Release 2 (11.2) for 64-bit Linux in a new Oracle Database home. It is recommended that you use the same version of Oracle Database home as on the 32-bit computer.
|
See Also: Oracle Database Installation Guide for Linux |
Edit init.ora file on the 64-bit computer to include the following changes:
Update the memory requirements included in the file.
The init.ora file still contains the 32-bit control file path. You must manually update control_files parameter value to include the 64-bit control file location.
|
Note: Oracle recommends that you double the values of shared pool, java pool,sga_target and large pool listed in the init.ora file. |
If the 64-bit target computer contains a different structure for data files, then you must re-create the control file or mount database on 64-bit computer. Refer to Re-aligning Data File Path and Name for more information.
|
Note: Oracle recommends not to use theRESETLOGS option to re-create control files. |
Set the system to spool results to a log file for later verification of success. For example:
SQL> SPOOL /tmp/utlirp.log
Run the following command on the 64-bit Oracle Database, to invalidate all the PL/SQL modules:
SQL> @$ORACLE_HOME/rdbms/admin/utlirp.sql
Turn off the spooling of script results to the log file:
SQL> SPOOL OFF;
Shut down the 64-bit Oracle Database:
SQL>shutdown immediate;
Start the 64-bit Oracle Database:
SQL> STARTUP pfile=init.ora;
If the JServer JAVA Virtual Machine component is installed, perform the following steps after connecting as SYS:
begin
update obj$ set status=5 where obj#=(select obj# from obj$,javasnm$
where owner#=0 and type#=29 and short(+)=name and
nvl(longdbcs,name)='oracle/aurora/rdbms/Compiler');
commit;
declare
cursor C1 is select
'DROP JAVA DATA "' || u.name || '"."' || o.name || '"'
from obj$ o,user$ u where o.type#=56 and u.user#=o.owner#;
ddl_statement varchar2(200);
iterations number;
previous_iterations number;
loop_count number;
my_err number;
begin
previous_iterations := 10000000;
loop
-- To make sure we eventually stop, pick a max number of iterations
select count(*) into iterations from obj$ where type#=56;
exit when iterations=0 or iterations >= previous_iterations;
previous_iterations := iterations;
loop_count := 0;
open C1;
loop
begin
fetch C1 into ddl_statement;
exit when C1%NOTFOUND or loop_count > iterations;
exception when others then
my_err := sqlcode;
if my_err = -1555 then -- snapshot too old, re-execute fetch query
exit;
else
raise;
end if;
end;
initjvmaux.exec(ddl_statement);
loop_count := loop_count + 1;
end loop;
close C1;
end loop;
end;
commit;
initjvmaux.drp('delete from java$policy$shared$table');
update obj$ set status=1 where obj#=(select obj# from obj$,javasnm$
where owner#=0 and type#=29 and short(+)=name and
nvl(longdbcs,name)='oracle/aurora/rdbms/Compiler');
commit;
end;
/
create or replace java system;
/
Revalidate all the existing PL/SQL modules in the format required by the 64-bit Oracle Database:
SQL>$ORACLE_HOME/rdbms/admin/utlrp.sql;
Re-aligning Data File Path and Name
The following are some methods to realign the data file names and path to point to the correct location:
Re-creating Control File
Perform the following steps to re-create the control file:
Run the following command to backup the control file to trace. The trace file is located under the diagnostic_dest directory on the 32-bit Linux computer. The following command generates a trace file which contains the necessary sql to re-create the control file:
SQL> alter database backup controlfile to trace;
|
Note: Ensure that you open the Oracle Database in theUPGRADE mode after the control file is created. |
Rename the trace file generated into .sql format on the 32-bit Linux computer. For example:
$ cp trace.ora control.sql
The contents of the control file are as follows, for example:
Re-creating control files with NORESETLOGS option.
32-bit control file with NORESETLOGS option:
STARTUP NOMOUNT pfile=t_init1.ora
CREATE CONTROLFILE REUSE DATABASE "L32" NORESETLOGS NOARCHIVELOG
MAXLOGFILES 32
MAXLOGMEMBERS 2
MAXDATAFILES 32
MAXINSTANCES 1
MAXLOGHISTORY 454
LOGFILE
GROUP 1 '/ade/aime_l32/oracle/dbs/t_log1.f' SIZE 25M,
GROUP 2 '/ade/aime_l32/oracle/dbs/t_log2.f' SIZE 25M
DATAFILE
'/ade/aime_l32/oracle/dbs/t_db1.f'
'/ade/aime_l32/oracle/dbs/t_ax1.f'
'/ade/aime_l32/oracle/dbs/t_undo1.f'
CHARACTER SET WE8DEC;
RECOVER DATABASE;
ALTER DATABASE OPEN UPGRADE;
ALTER TABLESPACE TEMP ADD TEMPFILE '/ade/aime_l32/oracle/dbs/t_tmp1.f' SIZE 41943040 REUSE AUTOEXTEND ON NEXT 8192 MAXSIZE 32767M;
Now, let us consider the modified 64-bit control file:
STARTUP NOMOUNT pfile=t_init1.ora
CREATE CONTROLFILE REUSE DATABASE "L32" NORESETLOGS NOARCHIVELOG
MAXLOGFILES 32
MAXLOGMEMBERS 2
MAXDATAFILES 32
MAXINSTANCES 1
MAXLOGHISTORY 454
LOGFILE
GROUP 1 '/ade/aime_l64/oracle/dbs/t_log1.f' SIZE 25M,
GROUP 2 '/ade/aime_l64/oracle/dbs/t_log2.f' SIZE 25M
DATAFILE
'/ade/aime_l64/oracle/dbs/t_db1.f'
'/ade/aime_l64/oracle/dbs/t_ax1.f'
'/ade/aime_l64/oracle/dbs/t_undo1.f'
CHARACTER SET WE8DEC;
RECOVER DATABASE;
ALTER DATABASE OPEN UPGRADE;
ALTER TABLESPACE TEMP ADD TEMPFILE '/ade/aime_l64/oracle/dbs/t_tmp1.f' SIZE 41943040 REUSE AUTOEXTEND ON NEXT 8192 MAXSIZE 32767M;
Re-creating control files with RESETLOGS option:
32-bit control file with RESETLOGS option:
STARTUP NOMOUNT pfile=t_init1.ora
CREATE CONTROLFILE REUSE DATABASE "L3žaé2" RESETLOGS NOARCHIVELOG
MAXLOGFILES 32
MAXLOGMEMBERS 2
MAXDATAFILES 32
MAXINSTANCES 1
MAXLOGHISTORY 454
LOGFILE
GROUP 1 '/ade/aime_l32/oracle/dbs/t_log1.f' SIZE 25M,
GROUP 2 '/ade/aime_l32/oracle/dbs/t_log2.f' SIZE 25M
DATAFILE
'/ade/aime_l32/oracle/dbs/t_db1.f'
'/ade/aime_l32/oracle/dbs/t_ax1.f'
'/ade/aime_l32/oracle/dbs/t_undo1.f'
CHARACTER SET WE8DEC;
RECOVER DATABASE USING BACKUP CONTROLFILE;
ALTER DATABASE OPEN RESETLOGS UPGRADE;
ALTER TABLESPACE TEMP ADD TEMPFILE '/ade/aime_l32/oracle/dbs/t_tmp1.f' SIZE 41943040 REUSE AUTOEXTEND ON NEXT 8192 MAXSIZE 32767M;
Now, let us consider the modified 64-bit control file:
STARTUP NOMOUNT pfile=t_init1.ora
CREATE CONTROLFILE REUSE DATABASE "L32" RESETLOGS NOARCHIVELOG
MAXLOGFILES 32
MAXLOGMEMBERS 2
MAXDATAFILES 32
MAXINSTANCES 1
MAXLOGHISTORY 454
LOGFILE
GROUP 1 '/ade/aime_l64/oracle/dbs/t_log1.f' SIZE 25M,
GROUP 2 '/ade/aime_l64/oracle/dbs/t_log2.f' SIZE 25M
DATAFILE
'/ade/aime_l64/oracle/dbs/t_db1.f'
'/ade/aime_l64/oracle/dbs/t_ax1.f'
'/ade/aime_l64/oracle/dbs/t_undo1.f'
CHARACTER SET WE8DEC;
RECOVER DATABASE USING BACKUP CONTROLFILE;
ALTER DATABASE OPEN RESETLOGS UPGRADE;
ALTER TABLESPACE TEMP ADD TEMPFILE '/ade/aime_l64/oracle/dbs/t_tmp1.f' SIZE 41943040 REUSE AUTOEXTEND ON NEXT 8192 MAXSIZE 32767M;
Based on the method employed to realign the file paths to point to the correct locations, you must copy the necessary files from the source 32-bit Linux computer to the target 64-bit Linux computer:
NORESETLOGS option: Copy init.ora, data files, re-created control files (control.sql), and the redo log files from the 32-bit Linux computer to the corresponding locations on the 64-bit Linux computer
RESETLOGS option: Copy init.ora, data files, and re-created control files (control.sql) from the 32-bit Linux computer to the corresponding locations on the 64-bit Linux computer
Connect to the database instance as SYSDBA:
SQL> CONNECT / AS SYSDBA;
To change from 32-bit to 64-bit, run the following command from the Linux 64-bit Oracle Database home:
sql>set echo on sql>@control.sql
Mounting Database on a 64-Bit Computer
Perform the following steps to mount the database on a 64-bit computer:
Copy init.ora, data files, control file and the redo log files from the 32-bit Linux computer to the corresponding locations on the 64-bit Linux computer
Connect to the database instance as SYSDBA:
SQL> CONNECT / AS SYSDBA;
Start the 64-bit Oracle Database as follows:
SQL> STARTUP mount pfile=init.ora;
Update all the 32-bit data file locations to include the 64-bit data file locations. For example:
sql> alter database rename file '/ade/aime_l32/oracle/dbs/t_db1.f' to '/ade/aime_l64/oracle/dbs/t_db1.f' sql> Database altered.
Update all the 32-bit log file locations to include the 64-bit log file locations. For example:
sql> alter database rename file '/ade/aime_l32/oracle/dbs/t_log.f' to '/ade/aime_l64/oracle/dbs/t_log.f' sql> Database altered.
To change from 32-bit to 64-bit, run the following command from the Linux 64-bit Oracle Database home:
sql> ALTER DATABASE OPEN UPGRADE;
To take advantage of Automatic Storage Management (ASM), you can migrate an Oracle 11g Release 2 (11.2) database into and out of an ASM disk group using Recovery Manager (RMAN). This migration is performed using RMAN even if you are not using RMAN for your primary backup and recovery strategy.
|
See Also: Chapter 8, "Performing ASM Data Migration with RMAN", in Oracle Automatic Storage Management Administrator's Guide for more information on migrating databases. |
This chapter provides information about administering Oracle Database on UNIX-based operating systems. It contains the following sections:
|
See Also: The appropriate appendix in this guide for platform-specific information about administering Oracle Database |
You must set Oracle Database environment variables, parameters, and user settings for Oracle Database to work. This chapter describes the various settings for Oracle Database.
In Oracle Database files and programs, a question mark (?) represents the value of the ORACLE_HOME environment variable. For example, Oracle Database expands the question mark in the following SQL statement to the full path of the Oracle home directory:
SQL> ALTER TABLESPACE TEMP ADD DATAFILE '?/dbs/temp02.dbf' SIZE 200M
Similarly, the at sign (@) represents the ORACLE_SID environment variable. For example, to indicate a file that belongs to the current instance, run the following command:
SQL> ALTER TABLESPACE tablespace_name ADD DATAFILE tempfile@.dbf
You can create a syslog audit trail to track administrative activities.
|
See Also: "Using the Syslog Audit Trail to Audit System Administrators on UNIX Systems" in Oracle Database Security Guide for more information on audit trails. |
This section describes the most commonly used Oracle Database and operating system environment variables. You must define some environment variables before installing Oracle Database. This section covers the following topics:
To display the current value of an environment variable, use the env command. For example, to display the value of the ORACLE_SID environment variable, run the following command:
$ env | grep ORACLE_SID
To display the current value of all environment variables, run the env command as follows:
$ env | more
Table 1-1 describes some environment variables used with Oracle Database.
Table 1-1 Oracle Database Environment Variables
| Variable | Detail | Definition |
|---|---|---|
|
|
Function |
Specifies the language, territory, and character set of the client environment. The client character set specified by Refer to Oracle Database Globalization Support Guide for a list of values for this variable. |
|
Syntax |
| |
|
Example |
| |
|
|
Function |
Specifies the directory where the language, territory, character set, and linguistic definition files are stored. |
|
Syntax |
| |
|
Example |
| |
|
Function |
Specifies the full path and file name of the time zone file. The Oracle Database Server always uses the large time zone file ( | |
|
Syntax |
| |
|
Example |
| |
|
Function |
Specifies the base of the Oracle directory structure for Optimal Flexible Architecture compliant installations. | |
|
Syntax |
| |
|
Example |
| |
|
Function |
Specifies the directory containing the Oracle software. | |
|
Syntax |
| |
|
Example |
| |
|
Function |
Specifies the search path for files used by Oracle applications such as SQL*Plus. If the full path to the file is not specified, or if the file is not in the current directory, then the Oracle application uses | |
|
Syntax |
Colon-separated list of directories: directory1:directory2:directory3 | |
|
Example |
Note: The period adds the current working directory to the search path. | |
|
Function |
Specifies the Oracle system identifier. | |
|
Syntax |
A string of numbers and letters that must begin with a letter. Oracle recommends a maximum of 8 characters for system identifiers. For more information about this environment variable, refer to Oracle Database Installation Guide. | |
|
Example |
SAL1 | |
|
Function |
Enables the tracing of shell scripts during an installation. If it is set to | |
|
Syntax |
| |
|
Example |
| |
|
Function |
Controls whether the | |
|
Syntax |
| |
|
Example |
| |
|
Function |
Specifies the directory or list of directories that SQL*Plus searches for a | |
|
Syntax |
Colon-separated list of directories: | |
|
Example |
| |
|
|
Function |
Specifies the directory containing the Oracle Net Services configuration files. |
|
Syntax |
| |
|
Example |
| |
|
Function |
Specifies the default connect identifier to use in the connect string. If this environment variable is set, then do not specify the connect identifier in the connect string. For example, if the
SQL> CONNECT USERNAME
Enter password: password
| |
|
Syntax |
Any connect identifier. | |
|
Range of Values |
Any valid connect identifier that can be resolved by using a naming method, such as a | |
|
Example |
| |
|
|
Function |
Specifies the Oracle character set name corresponding to the UNIX locale character set in which the file names and user names are encoded by the operating system. You must set the environment variable |
|
Syntax |
| |
|
Example |
|
|
Note: To prevent conflicts, do not define environment variables with names that are identical to the names of Oracle Database server processes, for exampleARCH, PMON, and DBWR. |
Table 1-2 describes UNIX environment variables used with Oracle Database.
Table 1-2 Environment Variables Used with Oracle Database
| Variable | Detail | Definition |
|---|---|---|
|
|
Function | |
|
Syntax |
| |
|
Example |
| |
|
|
Function |
For all precompiled applications where calculations are done using the extended precision of the x86 Floating Point Unit, this variable must be set to Note: Setting this variable results in non-IEEE compliant floating point results. Hence, |
|
Function |
Used with Java applications. The required setting for this variable depends on the Java application. Refer to the product documentation for Java application for more information. | |
|
Syntax |
Colon-separated list of directories or files: | |
|
Example |
There is no default setting.
| |
|
Function |
Used by X-based tools. Specifies the display device used for input and output. Refer to the X Window System documentation for information. | |
|
Syntax |
hostname:server[.screen] where Note: If you use a single monitor, then | |
|
Example |
135.287.222.12:0.0 bambi:0 | |
|
Syntax |
Colon-separated list of directories: | |
|
Example |
| |
|
Function |
The home directory of the user. | |
|
Syntax |
| |
|
Example |
| |
|
Function |
Specifies the language and character set used by the operating system for messages and other output. Oracle tools that are programmed in Java, such as Oracle Universal Installer and Oracle Database Configuration Assistant, may also use this variable to determine the language of their user interface. Refer to the operating system documentation for more information. | |
|
Function |
Specifies the default linker options. Refer to the | |
|
Function |
Specifies the name of the default printer. | |
|
Syntax |
| |
|
Example |
| |
|
Function |
Environment variable to specify the path used to search for libraries on UNIX and Linux. The environment variable may have a different name on some operating systems, such as | |
|
Syntax |
Colon-separated list of directories: | |
|
Example |
| |
|
Function |
Used by the shell to locate executable programs; must include the | |
|
Syntax |
Colon-separated list of directories: | |
|
Example |
Note: The period adds the current working directory to the search path. | |
|
Function |
Specifies the name of the default printer. | |
|
Syntax |
| |
|
Example |
| |
|
Function |
Specifies the default directories for temporary files; if set, tools that create temporary files create them in one of these directories. | |
|
Syntax |
| |
|
Example |
|
This section describes how to set a common operating system environment by using the oraenv or coraenv scripts, depending on the default shell:
For the Bourne, Bash, or Korn shell, use the oraenv command.
For the C shell, use the coraenv command.
oraenv and coraenv Script Files
The oraenv and coraenv scripts are created during installation. These scripts set environment variables based on the contents of the oratab file and provide:
A central means of updating all user accounts with database changes
A mechanism for switching between databases specified in the oratab file
You may find yourself frequently adding and removing databases from the development system or your users may be switching between several different Oracle Databases installed on the same system. You can use the oraenv or coraenv script to ensure that user accounts are updated and to switch between databases.
|
Note: Do not call theoraenv or coraenv script from the Oracle software owner (typically, oracle) user's shell startup script. Because these scripts prompt for values, they can prevent the dbstart script from starting a database automatically when the system starts. |
The oraenv or coraenv script is usually called from the user's shell startup file (for example, .profile or.login). It sets the ORACLE_SID and ORACLE_HOME environment variables and includes the $ORACLE_HOME/bin directory in the PATH environment variable setting. When switching between databases, users can run the oraenv or coraenv script to set these environment variables.
|
Note: To run one of these scripts, use the appropriate command:
|
The directory that contains the oraenv, coraenv, and dbhome scripts is called the local bin directory. All database users must have read access to this directory. Include the path of the local bin directory PATH environment variable setting for the users. When you run the root.sh script after installation, the script prompts you for the path of the local bin directory and automatically copies the oraenv, coraenv, and dbhome scripts to the directory that you specify. The default local bin directory is /usr/local/bin. If you do not run the root.sh script, then you can manually copy the oraenv or coraenv and dbhome scripts from the $ORACLE_HOME/bin directory to the local bin directory.
The TZ environment variable sets the time zone. It enables you to adjust the clock for daylight saving time changes or different time zones.
|
See Also: Oracle Database Globalization Support Guide and Oracle Database Administrator's Guide for more information about setting the database time zone |
The following sections provide information about Oracle Database initialization parameters:
The DB_BLOCK_SIZE initialization parameter specifies the standard block size for the database. This block size is used for the SYSTEM tablespace and by default in other tablespaces.
The maximum value to which you can set the DB_BLOCK_SIZE is 16 KB on Linux x86. It is 32 KB on other platforms.
|
Note: You cannot change the value of theDB_BLOCK_SIZE initialization parameter after you create a database. |
|
Note: Only Automatic Storage Management instances support theASM_DISKSTRING initialization parameter. |
The syntax for assigning a value to the ASM_DISKSTRING initialization parameter is as follows:
ASM_DISKSTRING = 'path1'[,'path2', . . .]
In this syntax, pathn is the path to a raw device. You can use wildcard characters when specifying the path.
Table 1-3 lists the platform-specific default values for the ASM_DISKSTRING initialization parameter.
The maximum value that you can set for ASYNC in the LOG_ARCHIVE_DEST_n initialization parameter differs on UNIX platforms as listed in the following table:
| Platform | Maximum Value |
|---|---|
| HP-UX | 51200 |
| Other operating systems | 102400 |
The DISK_ASYNCH_IO initialization parameter determines whether the database files reside on raw disks or file systems. Asynchronous I/O is available only with Automatic Storage Management disk group which uses raw partitions as the storage option for database files. The DISK_ASYNCH_IO parameter can be set to TRUE or FALSE depending on where the files reside. By default, the value is set to TRUE.
|
Note: TheDISK_ASYNCH_IO parameter must be set to FALSE when the database files reside on file system. This parameter must be set to TRUE only when the database files reside on raw partitions. |
This section describes the following special operating system accounts and groups that are required by Oracle Database:
If required, create additional operating system accounts. Users must be members of the OSDBA or OSOPER groups to connect to the database with administrator privileges.
Update the startup files of the oracle user and the operating system accounts of Oracle users, specifying the appropriate environment variables in the environment file.
For the Bourne, Bash, or Korn shell, add the environment variables to the .profile file, or the .bash_profile file for the Bash shell on Red Hat Enterprise Linux.
For the C shell, add the environment variables to the .login file.
|
Note: You can use theoraenv or coraenv script to ensure that Oracle user accounts are updated. |
This section describes the trace (or dump) that Oracle Database creates to help you diagnose and resolve operating problems.
Each server and background process writes to a trace file. When a process detects an internal error, it writes information about the error to its trace file. The file name format of a trace file is sid_processname_unixpid.trc, where:
sid is the instance system identifier
processname is a three or four-character abbreviated process name identifying the Oracle Database process that generated the file (for example, pmon, dbwr, ora, or reco)
unixpid is the operating system process ID number
The following is a sample trace file name:
$ORACLE_BASE/diag/rdbms/mydb/mydb/trace/test_lgwr_1237.trc
Set the MAX_DUMP_FILE initialization parameter to at least 5000, to ensure that the trace file is large enough to store error information.
This chapter describes how to configure Oracle Database for Oracle products. It contains the following sections:
Configuration assistants are usually run during an installation session, but you can also run them in standalone mode. As with Oracle Universal Installer, you can start each of the assistants noninteractively by using a response file.
This section contains the following topics:
When Oracle Net Server or Oracle Net Client is installed, Oracle Universal Installer automatically starts Oracle Net Configuration Assistant.
If you choose to perform a separate Oracle Database Client installation, then Oracle Net Configuration Assistant automatically creates a configuration that is consistent with the selections made during the installation. Oracle Universal Installer automatically runs Oracle Net Configuration Assistant to set up a net service name in the local naming file located in the $ORACLE_HOME/network/admin directory of the client installation.
After installation is complete, you can use Oracle Net Configuration Assistant to create a more detailed configuration by entering the following command:
$ $ORACLE_HOME/bin/netca
|
Note: When you use Oracle Database Configuration Assistant to create a database, it automatically updates the network configuration files to include information for the new database. |
During an Oracle Database installation, you can choose to upgrade a database from an earlier release to the current release. However, if you choose not to upgrade a database during installation or if there are multiple databases that you want to upgrade, then you can run Oracle Database Upgrade Assistant after the installation.
If you installed Oracle Database 11g and chose not to upgrade the database during the installation, then you must upgrade the database before mounting it.
To start Oracle Database Upgrade Assistant, run the following command:
$ $ORACLE_HOME/bin/dbua
For information about the command-line options available with Oracle Database Upgrade Assistant, use the -help or -h command-line arguments as follows:
$ $ORACLE_HOME/bin/dbua -help
|
See Also: Oracle Database Installation Guide and Oracle Database Upgrade Guide for more information about upgrades |
You can use Oracle Database Configuration Assistant to:
Create a default or customized database
Configure an existing database to use Oracle products
Create Automatic Storage Management disk groups
Generate a set of shell and SQL scripts that you can inspect, modify, and run at a later time to create a database
To start Oracle Database Configuration Assistant, run the following command:
$ $ORACLE_HOME/bin/dbca
For information about the command-line options available with Oracle Database Configuration Assistant, use the -help or -h command-line arguments as follows:
$ $ORACLE_HOME/bin/dbca -help
Oracle recommends that you run the utlrp.sql script after creating or upgrading a database. This script recompiles all PL/SQL modules that may be in an invalid state, including packages, procedures, and types. This is an optional step but Oracle recommends that you do it when you create the database and not at a later date.
To run the utlrp.sql script:
Switch user to oracle.
Use the oraenv or coraenv script to set the environment for the database on which you want to run the utlrp.sql script:
Bourne, Bash, or Korn shell:
$ . /usr/local/bin/oraenv
C shell:
% source /usr/local/bin/coraenv
When prompted, specify the SID for the database.
Run the following command to start SQL*Plus:
$ sqlplus "/ AS SYSDBA"
If required, run the following command to start the database:
SQL> STARTUP
Run the utlrp.sql script:
SQL> @?/rdbms/admin/utlrp.sql
You can relink the product executables manually by using the relink shell script located in the $ORACLE_HOME/bin directory. You must relink the product executables every time you apply an operating system patch or after an operating system upgrade.
|
Note: Before relinking executables, you must shut down all executables that run in the Oracle home directory that you are relinking. In addition, shut down applications linked with Oracle shared libraries.The |
Depending on the products that have been installed in the Oracle home directory, the relink script relinks all Oracle product executables.
|
See Also: "Accessing Oracle Database with SQL*Plus" in Oracle Database Installation Guide for Linux for more information on how to use the relink script with Automatic Storage Manager. |
To relink product executables, run the following command:
$ relink
This chapter describes how to identify Oracle Database processes, and provides basic information about how to stop and restart them. It also describes how to set up automatic startup and shutdown of the Oracle Database. It contains the following sections:
|
See Also: Oracle Database Administrator's Guide and Oracle Automatic Storage Management Administrator's Guide for more information about SRVCTL commands |
Starting with Oracle Database 11g Release 2 (11.2), the dbstart and dbshut scripts that were used to automate database startup and shutdown, are deprecated. Configure Oracle Database with the Oracle Restart feature to automatically restart the database, the listener, Oracle Automatic Storage Management (Oracle ASM), and other Oracle components after a hardware or software failure or when the database host computer restarts.
|
Note: When using Oracle Restart, you can use Service Control Utility (SRVCTL), a command-line interface, to manage Oracle processes (database instance, listener, ASM instance). With SRVCTL, you can manage the Oracle Restart configuration, see the status of processes managed by Oracle Restart, and start or stop processes such as the Oracle Database. SRVCTL has been enhanced to support single instance databases with Oracle Restart on standalone servers and on clusters with Oracle Clusterware. |
|
See Also: Configuring Automatic Restart of an Oracle Database in Oracle Database Administrator's Guide for more information about configuring automatic restart |
This section describes how to stop and start Oracle processes. It contains the following topics:
Stopping and Starting Oracle Database and Automatic Storage Management Instances
Stopping and Starting Oracle Enterprise Manager Database Control
This section describes how to stop and start Oracle Database and Automatic Storage Management instances.
|
Caution: Do not stop an Automatic Storage Management instance until you have stopped all Oracle Database instances that use that Automatic Storage Management instance to manage their storage. |
To stop an Oracle Database or Automatic Storage Management instance:
To identify the SID and Oracle home directory for the instance that should be shut down, run the following command:
On Solaris:
$ cat /var/opt/oracle/oratab
On other operating systems:
$ cat /etc/oratab
The oratab file contains lines similar to the following, which identify the SID and corresponding Oracle home directory for each database or Automatic Storage Management instance on the system:
sid:oracle_home_directory:[Y|N]
|
Note: Oracle recommends that you use the plus sign (+) as the first character in the SID of Automatic Storage Management instances. |
Depending on the default shell, run the oraenv or coraenv script to set the environment variables for the instance that should be shut down:
Bourne, Bash, or Korn shell:
$ . /usr/local/bin/oraenv
C shell:
% source /usr/local/bin/coraenv
When prompted, specify the SID for the instance.
Run the following commands to shut down the instance:
$ sqlplus
SQL> CONNECT SYS as SYSASM
Enter password: sys_password
SQL> SHUTDOWN NORMAL
After the instance shuts down, you can quit SQL*Plus.
|
Caution: If the database instance uses Automatic Storage Management for storage management, then you must start the Automatic Storage Management instance before you start the database instance. |
To restart an Oracle Database or Automatic Storage Management instance:
If required, repeat steps 1 and 2 to set the ORACLE_SID and ORACLE_HOME environment variables to identify the SID and Oracle home directory for the instance you want to start.
Run the following commands to start the instance:
$ sqlplus
SQL> CONNECT SYS as SYSASM
Enter password: sys_password
SQL> STARTUP
After the instance starts, you can exit from SQL*Plus.
The CRSCTL utility helps to start and stop Oracle Restart. The srvctl commands are no longer used to to start or stop Oracle Restart.
|
See Also: About Starting and Stopping Oracle Restart in Oracle Database Administrator's Guide for more information about starting and stopping Oracle Restart |
This section describes how to stop and start Oracle Enterprise Manager Database Control.
Stopping Oracle Enterprise Manager Database Control
To stop Oracle Enterprise Manager Database Control:
Depending on the default shell, run the oraenv or coraenv script to set the environment for the database managed by the Database Control that you want to stop:
coraenv script:
% source /usr/local/bin/coraenv
oraenv script:
$ . /usr/local/bin/oraenv
Run the following command to stop the Database Control:
$ $ORACLE_HOME/bin/emctl stop dbconsole
Starting Oracle Enterprise Manager Database Control
To start Database Control:
Set the ORACLE_SID and ORACLE_HOME environment variables to identify the SID and Oracle home directory for the database control that you want to start:
Bourne, Bash, or Korn shell:
$ ORACLE_HOME=oracle_home $ ORACLE_SID=sid $ export ORACLE_HOME ORACLE_SID
C shell:
% setenv ORACLE_HOME oracle_home % setenv ORACLE_SID sid
Run the following command to start the Database Control:
$ $ORACLE_HOME/bin/emctl start dbconsole
If you are using Oracle Enterprise Manager Grid Control to manage multiple Oracle products from a central location, then you must have an Oracle Management Agent installed on each host system. Typically, the Oracle Management Agent is installed in its own Oracle home directory.
This section describes how to stop and start Oracle Management Agent.
Stopping Oracle Management Agent
To stop Oracle Management Agent:
Run the following command to determine the Oracle home directory for Oracle Management Agent:
$ ps -ef | grep emagent
This command displays information about the Oracle Management Agent processes. The output of this command is similar to the following:
94248 ?? I 0:00.18 oracle_home/agent/bin/emagent ...
If required, set the ORACLE_HOME environment variable to specify the appropriate Oracle home directory for the Oracle Management Agent:
Bourne, Bash, or Korn shell:
$ ORACLE_HOME=oracle_home
$ export ORACLE_HOME
C shell:
% setenv ORACLE_HOME oracle_home
Run the following command to stop Oracle Management Agent:
$ $ORACLE_HOME/agent/bin/emctl stop agent
Starting Oracle Management Agent
To start Oracle Management Agent:
If required, set the ORACLE_HOME environment variable to specify the appropriate Oracle home directory for Oracle Management Agent:
Bourne, Bash, or Korn shell:
$ ORACLE_HOME=oracle_home
$ export ORACLE_HOME
C shell:
% setenv ORACLE_HOME oracle_home
Run the following command to start Oracle Management Agent:
$ $ORACLE_HOME/agent/bin/emctl start agent
This chapter describes how to build and run the SQL*Loader and PL/SQL demonstration programs available with Oracle Database. It contains the following sections:
|
Note: To use the demonstrations described in this chapter, you must install Oracle Database Examples included on the Oracle Database 11g Examples media. You must unlock JONES account and set the password before creating the demonstrations. |
Run the ulcase.sh file to run the SQL*Loader demonstrations. To run an individual demonstration, read the information contained in the file to determine how to run it.
PL/SQL includes many demonstration programs. You must build database objects and load sample data before using these programs. To build the objects and load the sample data:
Change directory to the PL/SQL demonstrations directory:
$ cd $ORACLE_HOME/plsql/demo
Start SQL*Plus, and enter the following command:
$ sqlplus
SQL> CONNECT JONES
Enter password: password
Run the following commands to build the objects and load the sample data:
SQL> @exampbld.sql SQL> @examplod.sql
|
Note: Build the demonstrations as any Oracle user with sufficient privileges. Run the demonstrations as the same Oracle user. |
The following PL/SQL kernel demonstrations are available with the software:
examp1.sql to examp8.sql
examp11.sql to examp14.sql
sample1.sql to sample4.sql
extproc.sql
To compile and run the exampn.sql or samplen.sql PL/SQL kernel demonstrations:
Start SQL*Plus, and enter the following command:
$ cd $ORACLE_HOME/plsql/demo
$ sqlplus
SQL> CONNECT JONES
Enter password: password
Run a command similar to the following to run a demonstration, where demo_name is the name of the demonstration:
SQL> @demo_name
To run the extproc.sql demonstration:
If required, add an entry for external procedures to the tnsnames.ora file, similar to the following:
EXTPROC_CONNECTION_DATA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS=(PROTOCOL = IPC)( KEY = EXTPROC))
)
(CONNECT_DATA =
(SID = PLSExtProc)
)
)
If required, add an entry for external procedures to the listener.ora file, similar to the following:
|
Note: The value that you specify for SID_NAME in thelistener.ora file must match the value that you specify for SID in the tnsnames.ora file. |
On HP-UX, Linux, and Solaris:
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC=
(SID_NAME=PLSExtProc)
(ORACLE_HOME=oracle_home_path)
(ENVS=EXTPROC_DLLS=oracle_home_path/plsql/demo/extproc.so,
LD_LIBRARY_PATH=oracle_home_path/plsql/demo)
(PROGRAM=extproc)
)
)
On AIX:
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC=
(SID_NAME=PLSExtProc)
(ORACLE_HOME=oracle_home_path)
(ENVS=EXTPROC_DLLS=oracle_home_path/plsql/demo/extproc.so,
LIBPATH=oracle_home_path/plsql/demo)
(PROGRAM=extproc)
)
)
Change directory to $ORACLE_HOME/plsql/demo.
Run the following command to create the extproc.so shared library, build the required database objects, and load the sample data:
$ make -f demo_plsql.mk extproc.so exampbld examplod
Alternatively, if you have already built the database objects and loaded the sample data, then run the following command:
$ make -f demo_plsql.mk extproc.so
From SQL*Plus, run the following commands:
SQL> CONNECT SYSTEM Enter password: system_password SQL> GRANT CREATE LIBRARY TO JONES; SQL> CONNECT JONES Enter password: password SQL> CREATE OR REPLACE LIBRARY demolib IS 2 'oracle_home_path/plsql/demo/extproc.so'; 3 /
|
Note: CREATE LIBRARY is a very high privilege. This privilege must be granted only to trusted users. |
To start the demonstration, run the following command:
SQL> @extproc
PL/SQL Precompiler Demonstrations
|
Note: Themake commands shown in this section build the required database objects and load the sample data in the JONES schema. |
The following precompiler demonstrations are available:
examp9.pc
examp10.pc
sample5.pc
sample6.pc
To build the PL/SQL precompiler demonstrations, set the library path environment variable to include the $ORACLE_HOME/lib directory, and run the following commands:
$ cd $ORACLE_HOME/plsql/demo $ make -f demo_plsql.mk demos
To build a single demonstration, run its name as the argument in the make command. For example, to build the examp9 demonstration, run the following command:
$ make -f demo_plsql.mk examp9
To start the examp9 demonstration, run the following command:
$ ./examp9
|
Note: This section applies to any 64-Bit Oracle Database. |
Starting with Oracle Database 11g release 2 (11.2), extproc32 is no longer available from 64-bit Oracle database install. Therefore, if you have a requirement to run 32-bit external procedures from 64-bit Oracle database, you must obtain 32-bit extproc by installing the corresponding 32-bit client software for your platform. Specifically, you must choose custom install within 32-bit client installation, and then select both Oracle Database Utilities and Oracle listener.
In other words, you need a separate Oracle home (32-bit) to run the 32-bit extproc. Note that the executable name is not extproc32 anymore, but simply extproc.
To enable 32-bit external procedures on 64-bit Oracle database environment, you must configure 32-bit listener for extproc and specify Oracle home (from the 32-bit client install) for the extproc listener.ora entry.
This chapter describes how to administer SQL*Plus. It contains the following sections:
This section describes how to administer command-line SQL*Plus. In the examples, SQL*Plus replaces the question mark (?) with the value of the ORACLE_HOME environment variable.
When you start SQL*Plus, it runs the glogin.sql site profile setup file and then runs the login.sql user profile setup file.
The global site profile file is $ORACLE_HOME/sqlplus/admin/glogin.sql. If a site profile exists at this location, then it is overwritten when you install SQL*Plus. If SQL*Plus is removed, then the site profile file is also removed.
The user profile file is login.sql. SQL*Plus looks for this file in the current directory, and then in the directories specified by the SQLPATH environment variable. The value of this environment variable is a colon-separated list of directories. SQL*Plus searches these directories for the login.sql file in the order that they are listed in the SQLPATH environment variable.
The options set in the login.sql file override those set in the glogin.sql file.
Oracle Database provides the PRODUCT_USER_PROFILE table that you can use to disable the specified SQL and SQL*Plus commands. This table is automatically created when you choose an installation type that installs a preconfigured database.
To re-create the PRODUCT_USER_PROFILE table, run the $ORACLE_HOME/sqlplus/admin/pupbld.sql script in the SYSTEM schema. For example, run the following commands, where SYSTEM_PASSWORD is the password of the SYSTEM user:
$ sqlplus
SQL> CONNECT SYSTEM
Enter password: system_password
SQL> @?/sqlplus/admin/pupbld.sql
You can also re-create the PRODUCT_USER_PROFILE table manually in the SYSTEM schema by using the $ORACLE_HOME/bin/pupbld shell script. This script prompts for the SYSTEM password. To run the pupbld script without interaction, then set the SYSTEM_PASS environment variable to the SYSTEM user name and password.
When you install Oracle Database or use Oracle Database Configuration Assistant to create a database, you can choose to install Oracle Database Sample Schemas.
|
See Also: Oracle Database Sample Schemas for information about installing and using Oracle Database Sample Schemas |
This section describes how to install and remove the SQL*Plus command-line Help.
|
See Also: SQL*Plus User's Guide and Reference for more information about the SQL*Plus command-line Help |
There are three ways to install the SQL*Plus command-line Help:
Complete an installation that installs a preconfigured database.
When you install a preconfigured database as part of an installation, SQL*Plus automatically installs the SQL*Plus command-line Help in the SYSTEM schema.
Install the command-line Help manually in the SYSTEM schema by using the $ORACLE_HOME/bin/helpins shell script.
The helpins script prompts for the SYSTEM password. To run this script without interaction, set the SYSTEM_PASS environment variable to the SYSTEM user name and password. For example:
Bourne, Bash, or Korn shell:
$ SYSTEM_PASS=SYSTEM/system_password; export SYSTEM_PASS
C shell:
% setenv SYSTEM_PASS SYSTEM/system_password
Install the command-line Help manually in the SYSTEM schema by using the $ORACLE_HOME/sqlplus/admin/help/helpbld.sql script.
For example, run the following commands, where system_password is the password of the SYSTEM user:
$ sqlplus
SQL> CONNECT SYSTEM
Enter password: system_password
SQL> @?/sqlplus/admin/help/helpbld.sql ?/sqlplus/admin/help helpus.sql
|
Note: Both thehelpins shell script and the helpbld.sql script drop existing command-line Help tables before creating new tables. |
To manually drop the SQL*Plus command-line Help tables from the SYSTEM schema, run the $ORACLE_HOME/sqlplus/admin/help/helpdrop.sql script. To do this, run the following commands, where system_password is the password of the SYSTEM user:
$ sqlplus
SQL> CONNECT SYSTEM
Enter password: system_password
SQL> @?/sqlplus/admin/help/helpdrop.sql
This section describes how to use command-line SQL*Plus. It contains the following topics:
If you run an ED or EDIT command at the SQL*Plus prompt, then the system starts an operating system editor, such as ed, emacs, ned, or vi. However, the PATH environment variable must include the directory where the editor executable is located.
When you start the editor, the current SQL buffer is placed in the editor. When you exit the editor, the changed SQL buffer is returned to SQL*Plus.
You can specify which editor should start by defining the SQL*Plus _EDITOR variable. You can define this variable in the glogin.sql site profile or the login.sql user profile. Alternatively, you can define it during the SQL*Plus session. For example, to set the default editor to vi, run the following command:
SQL> DEFINE _EDITOR=vi
If you do not set the _EDITOR variable, then the value of either the EDITOR or the VISUAL environment variable is used. If both environment variables are set, then the value of the EDITOR variable is used. If _EDITOR, EDITOR, and VISUAL are not specified, then the default editor is ed.
When you start the editor, SQL*Plus uses the afiedt.buf temporary file to pass text to the editor. You can use the SET EDITFILE command to specify a different file name. For example:
SQL> SET EDITFILE /tmp/myfile.sql
SQL*Plus does not delete the temporary file.
Using the HOST command or an exclamation point (!) as the first character after the SQL*Plus prompt causes subsequent characters to be passed to a subshell. The SHELL environment variable sets the shell used to run operating system commands. The default shell is the Bourne shell. If the shell cannot be run, then SQL*Plus displays an error message.
To return to SQL*Plus, run the exit command or press Ctrl+D.
For example, to run a single command, use the following command syntax:
SQL> ! command
In this example, command represents the operating system command that you want to run.
To run multiple operating system commands from SQL*Plus, run the HOST or! command. Press Enter to return to the operating system prompt.
While running SQL*Plus, you can stop the scrolling record display and terminate a SQL statement by pressing Ctrl+C.
This section describes the following SQL*Plus restrictions:
The default values for the SQL*Plus LINESIZE and PAGESIZE system variables do not automatically adjust for window size.
Operating system return codes use only one byte, which is not enough space to return an Oracle error code. The range for a return code is 0 to 255.
If you set the SYSTEM_PASS environment variable to the user name and password of the SYSTEM user, then the output of the ps command may display this information. To prevent unauthorized access, enter the SYSTEM password only when prompted by SQL*Plus.
To automatically run a script, consider using an authentication method that does not require you to store a password. For example, externally authenticated logins to Oracle Database. If you have a low-security environment, then you should consider using operating system pipes in script files to pass a password to SQL*Plus. For example:
$ echo system_password | sqlplus SYSTEM @MYSCRIPT
Alternatively, run the following commands:
$ sqlplus <<EOF
SYSTEM/system_password
SELECT ...
EXIT
EOF
In the preceding examples, system_passwsord is the password of the SYSTEM user.
This chapter describes how to tune Oracle Database. It contains the following sections:
The intent of this section is to efficiently tune and optimize the performance of Oracle Database. Frequent tuning enhances system performance and prevents data bottlenecks.
Before tuning the database, you must observe its normal behavior by using the tools described in the "Operating System Tools" section.
Several operating system tools are available to enable you to assess database performance and determine database requirements. In addition to providing statistics for Oracle processes, these tools provide statistics for CPU usage, interrupts, swapping, paging, context switching, and Input-Output for the entire system.
This section provides information about the following common tools:
|
See Also: The operating system documentation and man pages for more information about these tools |
Use the vmstat command to view process, virtual memory, disk, trap, and CPU activity, depending on the switches that you supply with the command. Run one of the following commands to display a summary of CPU activity six times, at five-second intervals:
On HP-UX and Solaris:
$ vmstat -S 5 6
On AIX and Linux:
$ vmstat 5 6
The following is sample output of this command on HP-UX:
procs memory page disk faults cpu r b w swap free si so pi po fr de sr f0 s0 s1 s3 in sy cs us sy id 0 0 0 1892 5864 0 0 0 0 0 0 0 0 0 0 0 90 74 24 0 0 99 0 0 0 85356 8372 0 0 0 0 0 0 0 0 0 0 0 46 25 21 0 0 100 0 0 0 85356 8372 0 0 0 0 0 0 0 0 0 0 0 47 20 18 0 0 100 0 0 0 85356 8372 0 0 0 0 0 0 0 0 0 0 2 53 22 20 0 0 100 0 0 0 85356 8372 0 0 0 0 0 0 0 0 0 0 0 87 23 21 0 0 100 0 0 0 85356 8372 0 0 0 0 0 0 0 0 0 0 0 48 41 23 0 0 100
The w sub column, under the procs column, shows the number of potential processes that have been swapped out and written to disk. If the value is not zero, then swapping occurs and the system is short of memory.
The si and so columns under the page column indicate the number of swap-ins and swap-outs per second, respectively. Swap-ins and swap-outs should always be zero.
The sr column under the page column indicates the scan rate. High scan rates are caused by a shortage of available memory.
The pi and po columns under the page column indicate the number of page-ins and page-outs per second, respectively. It is normal for the number of page-ins and page-outs to increase. Some paging always occurs even on systems with sufficient available memory.
|
Note: The output from thevmstat command differs across platforms. |
|
See Also: Refer to the man page for information about interpreting the output |
Depending on the switches that you supply with the command, use the sar (system activity reporter) command to display cumulative activity counters in the operating system.
On an HP-UX system, the following command displays a summary of Input-Output activity every ten seconds:
$ sar -b 10 10
The following example shows the output of this command:
13:32:45 bread/s lread/s %rcache bwrit/s lwrit/s %wcache pread/s pwrit/s 13:32:55 0 14 100 3 10 69 0 0 13:33:05 0 12 100 4 4 5 0 0 13:33:15 0 1 100 0 0 0 0 0 13:33:25 0 1 100 0 0 0 0 0 13:33:35 0 17 100 5 6 7 0 0 13:33:45 0 1 100 0 0 0 0 0 13:33:55 0 9 100 2 8 80 0 0 13:34:05 0 10 100 4 4 5 0 0 13:34:15 0 7 100 2 2 0 0 0 13:34:25 0 0 100 0 0 100 0 0 Average 0 7 100 2 4 41 0 0
The sar output provides a snapshot of system Input-Output activity at a given point in time. If you specify the interval time with multiple options, then the output can become difficult to read. If you specify an interval time of less than 5, then the sar activity itself can affect the output.
|
See Also: The man page for more information aboutsar |
Use the iostat command to view terminal and disk activity, depending on the switches that you supply with the command. The output from the iostat command does not include disk request queues, but it shows which disks are busy. You can use this information to balance the Input-Output loads.
The following command displays terminal and disk activity five times, at five-second intervals:
$ iostat 5 5
The following is sample output of the command on Solaris:
tty fd0 sd0 sd1 sd3 cpu tin tout Kps tps serv Kps tps serv Kps tps serv Kps tps serv us sy wt id 0 1 0 0 0 0 0 31 0 0 18 3 0 42 0 0 0 99 0 16 0 0 0 0 0 0 0 0 0 1 0 14 0 0 0 100 0 16 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 100 0 16 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 100 0 16 0 0 0 0 0 0 2 0 14 12 2 47 0 0 1 98
Use the iostat command to look for large disk request queues. A request queue shows how long the Input-Output requests on a particular disk device must wait to be serviced. Request queues are caused by a high volume of Input-Output requests to that disk or by Input-Output with long average seek times. Ideally, disk request queues should be at or near zero.
Use the swap, swapinfo, swapon, or lsps command to report information about swap space usage. A shortage of swap space can stop processes responding, leading to process failures with Out of Memory errors. The following table lists the appropriate command to use for each platform:
| Platform | Command |
|---|---|
| AIX | lsps -a |
| HP-UX | swapinfo -m |
| Linux | swapon -s |
| Solaris | swap -l and swap -s |
The following example shows sample output from the swap -l command on Solaris:
swapfile dev swaplo blocks free /dev/dsk/c0t3d0s1 32,25 8 197592 162136
The following sections describe tools available on AIX systems:
|
See Also: The AIX operating system documentation and man pages for more information about these tools |
The AIX Base Operation System contains performance tools that are historically part of UNIX systems or are required to manage the implementation-specific features of AIX. The following table lists the most important Base Operation System tools:
| Tool | Function |
|---|---|
lsattr | Displays the attributes of devices |
lslv | Displays information about a logical volume or the logical volume allocations of a physical volume |
netstat | Displays the contents of network-related data structures |
nfsstat | Displays statistics about Network File System and Remote Procedure Call activity |
nice | Changes the initial priority of a process |
no | Displays or sets network options |
ps | Displays the status of one or more processes |
reorgvg | Reorganizes the physical-partition allocation within a volume group |
time | Displays the elapsed execution, user CPU processing, and system CPU processing time |
trace | Records and reports selected system events |
vmo | Manages Virtual Memory Manager tunable parameters |
The AIX Performance Toolbox contains tools for monitoring and tuning system activity locally and remotely. The Performance Tool Box consists of two main components, the Performance Tool Box Manager and the Performance Tool Box Agent. The Performance Tool Box Manager collects and displays data from various systems in the configuration by using the xmperf utility. The Performance Tool Box Agent collects and transmits data to the Performance Tool Box Manager by using the xmserd daemon. The Performance Tool Box Agent is also available as a separate product called Performance Aide for AIX.
Both Performance Tool Box and Performance Aide include the monitoring and tuning tools listed in the following table:
| Tool | Description |
|---|---|
fdpr | Optimizes an executable program for a particular workload |
filemon | Uses the trace facility to monitor and report the activity of the file system |
fileplace | Displays the placement of blocks of a file within logical or physical volumes |
lockstat | Displays statistics about contention for kernel locks |
lvedit | Facilitates interactive placement of logical volumes within a volume group |
netpmon | Uses the trace facility to report on network Input-Output and network-related CPU usage |
rmss | Simulates systems with various memory sizes for performance testing |
svmon | Captures and analyzes information about virtual-memory usage |
syscalls | Records and counts system calls |
tprof | Uses the trace facility to report CPU usage at module and source-code-statement levels |
BigFoot | Reports the memory access patterns of processes |
stem | Permits subroutine-level entry and exit instrumentation of existing executables |
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See Also:
|
The following performance analysis tools are available on HP-UX systems:
This HP-UX utility is an online diagnostic tool that measures the activities of the system. GlancePlus displays information about how system resources are used. It displays dynamic information about the system Input-Output, CPU, and memory usage on a series of screens. You can use the utility to monitor how individual processes are using resources.
HP Programmer's Analysis Kit consists of the following tools:
Puma
This tool collects performance statistics during a program run. It provides several graphical displays for viewing and analyzing the collected statistics.
Thread Trace Visualizer
This tool displays trace files produced by the instrumented thread library, libpthread_tr.sl, in a graphical format. It enables you to view how threads are interacting and to find where threads are blocked waiting for resources.
HP Programmer's Analysis Kit is bundled with the HP Fortran 77, HP Fortran 90, HP C, HP C++, HP ANSI C++, and HP Pascal compilers.
The following table lists the performance tuning tools that you can use for additional performance tuning on HP-UX:
| Tools | Function |
|---|---|
caliper (Itanium only) | Collects run-time application data for system analysis tasks such as cache misses, translation look-aside buffer or instruction cycles, along with fast dynamic instrumentation. It is a dynamic performance measurement tool for C, C++, Fortran, and assembly applications. |
gprof | Creates an execution profile for programs. |
monitor | Monitors the program counter and calls to certain functions. |
netfmt | Monitors the network. |
netstat | Reports statistics on network performance. |
nfsstat | Displays statistics about Network File System and Remote Procedure Call activity. |
nettl | Captures network events or packets by logging and tracing. |
prof | Creates an execution profile of C programs and displays performance statistics for the program, showing where the program is spending most of its execution time. |
profil | Copies program counter information into a buffer. |
top | Displays the top processes on the system and periodically updates the information. |
On Linux systems, use the top, free, and cat /proc/meminfo commands to view information about swap space, memory, and buffer usage.
On Solaris systems, use the mpstat command to view statistics for each processor in a multiprocessor system. Each row of the table represents the activity of one processor. The first row summarizes all activity since the last system restart. Each subsequent row summarizes activity for the preceding interval. All values are events per second unless otherwise noted. The arguments are for time intervals between statistics and number of iterations.
The following example shows sample output from the mpstat command:
CPU minf mjf xcal intr ithr csw icsw migr smtx srw syscl usr sys wt idl 0 0 0 1 71 21 23 0 0 0 0 55 0 0 0 99 2 0 0 1 71 21 22 0 0 0 0 54 0 0 0 99 CPU minf mjf xcal intr ithr csw icsw migr smtx srw syscl usr sys wt idl 0 0 0 0 61 16 25 0 0 0 0 57 0 0 0 100 2 1 0 0 72 16 24 0 0 0 0 59 0 0 0 100
Start the memory tuning process by measuring paging and swapping space to determine how much memory is available. After you determine the system memory usage, tune the Oracle buffer cache.
The Oracle buffer manager ensures that the most frequently accessed data is cached longer. If you monitor the buffer manager and tune the buffer cache, then you can significantly improve Oracle Database performance. The optimal Oracle Database buffer size for the system depends on the overall system load and the relative priority of Oracle Database over other applications.
This section includes the following topics:
Try to minimize swapping because it causes signific €ÿant operating system overhead. To check for swapping, use the sar or vmstat commands. For information about the appropriate options to use with these commands, refer to the man pages.
If the system is swapping and you must conserve memory, then:
Avoid running unnecessary system daemon processes or application processes.
Decrease the number of database buffers to free some memory.
Decrease the number of operating system file buffers.
To determine the amount of swap space, run one of the following commands, depending on the platform:
| Platform | Command |
|---|---|
| AIX | lsps -a |
| HP-UX | swapinfo -m |
| Linux | swapon -s |
| Solaris | swap -l and swap -s |
To add swap space to the system, run one of the following commands, depending on the platform:
| Platform | Command |
|---|---|
| AIX | chps or mkps |
| HP-UX | swapon |
| Linux | swapon -a |
| Solaris | swap -a |
Set the swap space to the level listed for your platform in the respective platform-specific installation guide, based on your physical RAM and memory features used.
|
See Also:
|
Paging may not present as serious a problem as swapping, because an entire program does not have to be stored in memory to run. A small number of page-outs may not noticeably affect the performance of the system.
To detect excessive paging, run measurements during periods of fast response or idle time to compare against measurements from periods of slow response.
Use the vmstat or sar command to monitor paging.
|
See Also: The man pages or the operating system documentation for information about interpreting the results for the platform |
The following table lists the important columns from the output of these commands:
| Platform | Column | Function |
|---|---|---|
| Solaris | vflt/s | Indicates the number of address translation page faults. Address translation faults occur when a process refers to a valid page not in memory. |
| HP-UX | at | Indicates the number of address translation page faults. Address translation faults occur when a process refers to a valid page not in memory. |
| HP-UX | re | Indicates the number of valid pages that have been reclaimed and added to the free list by page-out activity. This value should be zero. |
If the system consistently has excessive page-out activity, then consider the following solutions:
Install more memory.
Move some work to another system.
Configure the System Global Area (SGA) to use less memory.
During read operations, entire operating system blocks are read from the disk. If the database block size is smaller than the operating system file system block size, then Input-Output bandwidth is inefficient. If you set Oracle Database block size to be a multiple of the file system block size, then you can increase performance by up to 5 percent.
The DB_BLOCK_SIZE initialization parameter sets the database block size. However, to change the value of this parameter, you must re-create the database.
To see the current value of the DB_BLOCK_SIZE parameter, run the SHOW PARAMETER DB_BLOCK_SIZE command in SQL*Plus.
You can set parameters to automatically allocate memory based on the demands of workload and the requirements of various database instances running on the same system. The MEMORY_TARGET parameter specifies the Oracle systemwide usable memory for that instance and automatically tunes SGA and Process Global Area (PGA) components. The MEMORY_MAX_TARGET parameter identifies the value up to which the MEMORY_TARGET parameter can grow dynamically.
By default, the value for both these parameters is zero and there is no auto-tuning. You can activate auto-tuning by setting the MEMORY_TARGET parameter to a nonzero value. To dynamically enable the MEMORY_TARGET parameter, the MEMORY_MAX_TARGET parameter must be set at startup.
|
Note: If you just set theMEMORY_TARGET parameter to a nonzero value, the MEMORY_MAX_TARGET parameter automatically acquires this value.
The On Solaris, Dynamic Intimate Shared Memory is enabled for On Linux, some shared resource requirements are increased when |
|
Tip: You can set theMEMORY_TARGET and MEMORY_MAX_TARGET parameters based on original setup, memory available for Oracle on the computer, and workload memory requirements. |
Balance Input-Output evenly across all available disks to reduce disk access times. For smaller databases and those not using RAID, ensure that different data files and tablespaces are distributed across the available disks.
This section contains the following topics:
If you choose to use Automatic Storage Management for database storage, then all database Input-Output is balanced across all available disk devices in the Automatic Storage Management disk group.
By using Automatic Storage Management, you avoid manually tuning disk Input-Output.
Depending on the operating system, you can choose from a range of file system types. Each file system type has different characteristics. This fact can have a substantial impact on database performance. The following table lists common file system types:
The suitability of a file system for an application is usually not documented. For example, even different implementations of the Unified file system are hard to compare. Depending on the file system that you choose, performance differences can be up to 20 percent. If you choose to use a file system, then:
Make a new file system partition to ensure that the hard disk is clean and unfragmented.
Perform a file system check on the partition before using it for database files.
Distribute disk Input-Output as evenly as possible.
If you are not using a logical volume manager or a RAID device, then consider placing log files on a different file system from data files.
The following sections describe the procedure for monitoring disk performance:
To monitor disk performance, use the sar -b and sar -u commands.
The following table describes the columns of the sar -b command output that are significant for analyzing disk performance:
| Columns | Description |
|---|---|
bread/s, bwrit/s | Blocks read and blocks written per second (important for file system databases) |
pread/s, pwrit/s | Number of reads and writes per second from or to raw character devices |
An important sar -u column for analyzing disk performance is %wio, the percentage of CPU time spent waiting on blocked Input-Output.
|
Note: Not all Linux distributions display the%wio column in the output of the sar -u command. For detailed Input-Output statistics, you can use iostat -x command. |
Key indicators are:
The sum of the bread, bwrit, pread, and pwrit column values indicates the level of activity of the disk Input-Output subsystem. The higher the sum, the busier the Input-Output subsystem. The larger the number of physical drives, the higher the sum threshold number can be. A good default value is no more than 40 for 2 drives and no more than 60 for 4 to 8 drives.
The %rcache column value should be greater than 90 and the %wcache column value should be greater than 60. Otherwise, the system may be disk Input-Output bound.
If the %wio column value is consistently greater than 20, then the system is Input-Output bound.
Use the alter diskgroup disk online and alter diskgroup disk offline commands to temporarily suspend Input-Output to a set of disks. You can use these commands to perform regular maintenance tasks or upgrades such as disk firmware upgrade. If transient failures occur on some disks in a disk group, then use alter diskgroup disk online to quickly recover the disk group.
The SGA is the Oracle structure that is located in shared memory. It contains static data structures, locks, and data buffers.
The maximum size of a single shared memory segment is specified by the shmmax kernel parameter.
The following table shows the recommended value for this parameter, depending on the platform:
| Platform | Recommended Value |
|---|---|
| AIX | NA |
| HP-UX | The size of the physical memory installed on the system
See Also: HP-UX Shared Memory Segments for an Oracle Instance for information about the |
| Linux | Minimum of the following values:
|
| Solaris | 4294967295 or 4 GB minus 16 MB
Note: If the system runs both Oracle9i Database and Oracle Database 11g instances, then you must set the value of |
If the size of the SGA exceeds the maximum size of a shared memory segment (shmmax or shm_max), then Oracle Database attempts to attach more contiguous segments to fulfill the requested SGA size. The shmseg kernel parameter specifies the maximum number of segments that can be attached by any process. Set the following initialization parameters to control the size of the SGA:
Alternatively, set the SGA_TARGET initialization parameter to enable automatic tuning of the SGA size.
|
Note: Ensure that you set the values for these parameters correctly. When values are set too high, too much of the physical memory is devoted to shared memory. This results in poor performance. |
An Oracle Database configured with Shared Server requires a higher setting for the SHARED_POOL_SIZE initialization parameter, or a custom configuration that uses the LARGE_POOL_SIZE initialization parameter. If you installed the database with Oracle Universal Installer, then the value of the SHARED_POOL_SIZE parameter is set automatically by Oracle Database Configuration Assistant. However, if you created a database manually, then increase the value of the SHARED_POOL_SIZE parameter in the parameter file by 1 KB for each concurrent user.
Sufficient shared memory must be available to each Oracle process to address the entire SGA:
You can determine the SGA size in one of the following ways:
Run the following SQL*Plus command to display the size of the SGA for a running database:
SQL> SHOW SGA
The result is shown in bytes.
When you start the database instance, the size of the SGA is displayed next to the Total System Global Area heading.
Run the ipcs command as the oracle user.
The System Resource Verifier utility (sysresv) is available with Oracle Database 8i and later releases. It provides Oracle instance and operating system resource information for the Oracle system identifiers (ORACLE_SID) that you specify. This utility is located in $ORACLE_HOME/bin, but it can be used from other locations.
Use the sysresv utility to display the status of an Oracle instance and identify the operating system resources it uses, such as the memory and semaphore parameters. This utility is especially useful when multiple instances are running. For example, if an instance is not responsive, then you can use this utility to remove operating system resources.
You can use this utility when an Oracle instance has crashed or was aborted, and memory and semaphores related to this instance were not cleaned up automatically. This utility is also useful in determining which Oracle instance is running.
To use the sysresv utility, you must have access to the System Global Area (SGA). To access the SGA, you must be the Oracle owner or a member of the group that owns the Oracle binary.
The syntax for the sysresv utility is as follows:
sysresv [-i] [-f] [-d on|off] [-l sid1[ sid2 ...]]
Where:
-i Prompt before removing IPC resources for each sid
-f Remove IPC resources without prompting for confirmation. This flag overrides the -i option
-d on|off List IPC resources for each sid if on. If not specified, the default for -d is on
-l sid1 [sid2 sid3] run the sysresv check against one or more space-delimited system identifiers
If sysresv is used without flags, then it reports IPC resources for the Oracle instance identified by the $ORACLE_SID environment variable in the Oracle installation owner user profile list of environment variables.
|
Note: The information in this section applies only to AIX. |
Shared memory uses common virtual memory resources across processes. Processes share virtual memory segments through a common set of virtual memory translation resources, for example, tables and cached entries, for improved performance.
Shared memory can be pinned to prevent paging and to reduce Input-Output overhead. To perform this, set the LOCK_SGA parameter tåço true. On AIX 5L, the same parameter activates the large page feature whenever the underlying hardware supports it.
Run the following command to make pinned memory available to Oracle Database:
$ /usr/sbin/vmo -r -o v_pinshm=1
Run a command similar to the following to set the maximum percentage of real memory available for pinned memory, where percent_of_real_memory is the maximum percent of real memory that you want to set:
$ /usr/sbin/vmo -r -o maxpin percent=percent_of_real_memory
When using the maxpin percent option, it is important that the amount of pinned memory exceeds the Oracle SGA size by at least 3 percent of the real memory on the system, enabling free pinnable memory for use by the kernel. For example, if you have 2 GB of physical memory and you want to pin the SGA by 400 MB (20 percent of the RAM), then run the following command:
$ /usr/sbin/vmo -r -o maxpin percent=23
|
Note: The defaultmaxpin percent value, which is set at 80 percent, works for most installations. |
Use the svmon command to monitor the use of pinned memory during the operation of the system. Oracle Database attempts to pin memory only if the LOCK_SGA parameter is set to true. If the SGA size exceeds the size of memory available for pinning, then the portion of the SGA exceeding these sizes is allocated to ordinary shared memory.
Large Page Feature on AIX POWER4- and POWER5-Based Systems
To turn on and reserve 10 large pages each of size 16 MB on a POWER4 or POWER 5 system, run the following command:
$ /usr/sbin/vmo -r -o lgpg_regions=10 -o lgpg_size=16777216
This command proposes bosboot and warns that a restart is required for the changes to take affect.
Oracle recommends specifying enough large pages to contain the entire SGA. The Oracle database instance attempts to allocate large pages when the LOCK_SGA parameter is set to true.
The 16 MB pages are always pinned, and cannot be used for standard memory. If a pool of 16MB size pages is configured, then this memory will be unusable for allocation of standard memory even if no other application is currently using large pages.
The POWER5 based systems support 64 K pages. Oracle uses them for SGA if they are available. These 64K pages do not require any additional configuration and do not depend on LOCK_SGA parameter setting.
To monitor use of large pages, use the following command:
$ vmstat -P all
For the AIX operating system to use 16MB pages, or pinned memory when allocating shared memory, the Oracle user ID must have CAP_BYPASS_RAC_VMM and CAP_PROPAGATE capabilities. User ID that is used to start the database instance must also have the same capabilities. In particular, when using large pages on an Oracle Real Application Cluster (Oracle RAC) database, where the srvctl command is used to start and stop the Oracle RAC database instances, it is also necessary to set the CAP_BYPASS_RAC_VMM and CAP_PROPAGATE capabilities for the root user.
|
See Also: The AIX documentation for more information about enabling and tuning pinned memory and large pages |
Capabilities can be set and examined using the following commands:
Run the following command to check the current capabilities:
$ lsuser –a capabilities oracle
Add the CAP_BYPASS_RAC_VMM and CAP_PROPAGATE capabilities to this user ID:
$ chuser capabilities=CAP_BYPASS_RAC_VMM,CAP_PROPAGATE oracle
|
Note: Only theroot user can display and set the capabilities attribute. |
Adjust the size of Oracle Database buffer cache. If memory is limited, then adjust the operating system buffer cache.
The operating system buffer cache holds blocks of data in memory while they are being transferred from memory to disk, or from disk to memory.
Oracle Database buffer cache is the area in memory that stores Oracle Database buffers.
If the amount of memory on the system is limited, then make a corresponding decrease in the operating system buffer cache size.
Use the sar command to determine which buffer caches you must increase or decrease.
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This chapter describes how to configure Oracle Net Services. It contains the following sections:
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See Also: Oracle Database Net Services Administrator's Guide for more information about Oracle Net Services |
Oracle Net Services configuration files are typically, but not always, located in the $ORACLE_HOME/network/admin directory. Depending on the type of file, Oracle Net uses a different search order to locate the file.
The search order for the sqlnet.ora and ldap.ora files is as follows:
The directory specified by the TNS_ADMIN environment variable, if this environment variable is set
The $ORACLE_HOME/network/admin directory
The search order for the cman.ora, listener.ora, and tnsnames.ora files is as follows:
The directory specified by the TNS_ADMIN environment variable, if this environment variable is set
One of the following directories:
On Solaris:
/var/opt/oracle
On other platforms:
/etc
The $ORACLE_HOME/network/admin directory
For some system-level configuration files, users may have a corresponding user-level configuration file stored in their home directory. The settings in the user-level file override the settings in the system-level file. The following table lists the system-level configuration files and the corresponding user-level configuration files:
| System-Level Configuration File | User-Level Configuration File |
|---|---|
sqlnet.ora | $HOME/.sqlnet.ora |
tnsnames.ora | $HOME/.tnsnames.ora |
Sample Configuration Files
The $ORACLE_HOME/network/admin/samples directory contains samples of the cman.ora, listener.ora, sqlnet.ora, and tnsnames.ora configuration files.
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Note: Thecman.ora file is installed only if you select Connection Manager as part of a custom installation. |
Use the adapters utility to display the transport protocols, naming methods, and Oracle Advanced Security options that Oracle Database supports on the system. To use the adapters utility, run the following commands:
$ cd $ORACLE_HOME/bin $ adapters ./oracle
On an Oracle Database Client system, the adapters utility displays output similar to the following:
Oracle Net transport protocols linked with ./oracle are
IPC
BEQ
TCP/IP
SSL
RAW
Oracle Net naming methods linked with ./oracle are:
Local Naming (tnsnames.ora)
Oracle Directory Naming
Oracle Host Naming
NIS Naming
Oracle Advanced Security options linked with ./oracle are:
RC4 40-bit encryption
RC4 128-bit encryption
RC4 256-bit encryption
DES40 40-bit encryption
DES 56-bit encryption
3DES 112-bit encryption
3DES 168-bit encryption
AES 128-bit encryption
AES 192-bit encryption
SHA crypto-checksumming (for FIPS)
SHA-1 crypto-checksumming
Kerberos v5 authentication
RADIUS authentication
ENTRUST authentication
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See Also: Oracle Database Net Services Administrator's Guide for more information about theadapters utility |
Oracle protocol support is a component of Oracle Net. It includes the following:
The IPC, TCP/IP, and TCP/IP with Secure Sockets Layer protocol supports each have an address specification that is used in Oracle Net Services configuration files and in the DISPATCHER initialization parameter. The following sections describe the address specifications for each of the protocol supports.
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See Also: Oracle Database Net Services Administrator's Guide for more information about Oracle protocol support |
The IPC protocol support can be used only when the client program and Oracle Database are installed on the same system. This protocol support requires a listener. It is installed and linked to all client tools and the oracle executable.
The IPC protocol support requires an address specification in the following format:
(ADDRESS = (PROTOCOL=IPC)(KEY=key))
The following table describes the parameters used in this address specification:
| Parameter | Description |
|---|---|
| PROTOCOL | The protocol to be used. The value is IPC. It is not case-sensitive. |
| KEY | Any name that is different from any other name used for an IPC KEY on the same system. |
The following is a sample IPC protocol address:
(ADDRESS= (PROTOCOL=IPC)(KEY=EXTPROC))
TCP/IP is the standard communication protocol used for client/server communication over a network. The TCP/IP protocol support enables communication between client programs and Oracle Database, whether they are installed on the same or different systems. If the TCP/IP protocol is installed on the system, then the TCP/IP protocol support is installed and linked to all client tools and to the oracle executable.
The TCP/IP protocol support requires an address specification in the following format:
(ADDRESS = (PROTOCOL=TCP)(HOST=hostname)(PORT=port))
The following table describes the parameters used in this address specification:
| Parameter | Description |
|---|---|
| PROTOCOL | The protocol support to be used. The value is TCP. It is not case-sensitive. |
| HOST | The host name or the host IP address. |
| PORT | The TCP/IP port. Specify the port as either a number or the alias name mapped to the port in the /etc/services file. Oracle recommends a value of 1521. |
The following is a sample TCP/IP protocol address:
(ADDRESS= (PROTOCOL=TCP)(HOST=MADRID)(PORT=1521))
The TCP/IP with Secure Sockets Layer protocol support enables an Oracle application on a client to communicate with remote Oracle Database instances through TCP/IP and Secure Sockets Layer. To use TCP/IP with Secure Sockets Layer, you must install Oracle Advanced Security.
The TCP/IP with Secure Sockets Layer protocol support requires an address specification in the following format:
(ADDRESS = (PROTOCOL=TCPS)(HOST=hostname)(PORT=port))
The following table describes the parameters used in this address specification:
| Parameter | Description |
|---|---|
| PROTOCOL | The protocol to be used. The value is TCPS. It is not case-sensitive. |
| HOST | The host name or the host IP address. |
| PORT | The TCP/IP with Secure Sockets Layer port. Specify the port as either a number or the alias name mapped to the port in the /etc/services file. Oracle recommends a value of 2484. |
The following is a sample TCP/IP with Secure Sockets Layer protocol address:
(ADDRESS= (PROTOCOL=TCPS)(HOST=MADRID)(PORT=2484))
Oracle recommends that you reserve a port for the listener in the /etc/services file of each Oracle Net Services node on the network. The default port is 1521. The entry lists the listener name and the port number. For example:
oraclelistener 1521/tcp
In this example, oraclelistener is the name of the listener as defined in the listener.ora file. Reserve multiple ports if you intend to start multiple listeners.
If you intend to use Secure Sockets Layer, then you should define a port for TCP/IP with Secure Sockets Layer in the /etc/services file. Oracle recommends a value of 2484. For example:
oraclelistenerssl 2484/tcps
In this example, oraclelistenerssl is the name of the listener as defined in the listener.ora file. Reserve multiple ports if you intend to start multiple listeners.
This appendix describes database limits.
Table F-1 lists the default and maximum values for parameters in a CREATE DATABASE or CREATE CONTROLFILE statement.
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Note: Interdependencies between these parameters may affect permissible values. |
Table F-1 CREATE CONTROLFILE and CREATE DATABASE Parameters
| Parameter | Default | Maximum Value |
|---|---|---|
|
16 |
255 | |
|
2 |
5 | |
|
100 |
65534 | |
|
30 |
65534 | |
|
1 |
1055 |
Table F-2 lists the Oracle Database file size limits in bytes.
Table F-2 File Size Limits
| File Type | Platform | File size limit |
|---|---|---|
|
Data files |
Any |
4,194,303 multiplied by the value of the |
|
Import/Export files and SQL*Loader files |
AIX, HP-UX, Linux, and Solaris: 32-bit with 32-bit files |
2,147,483,647 bytes |
|
AIX, HP-UX, Linux, and Solaris: 64-bit files |
Unlimited Note: File size is limited by limits allowed by the operating system on different file systems. | |
|
Control files |
HP-UX, Linux, AIX, and Solaris |
25000 control file blocks with a block size of 4096 bytes. |