This chapter describes how to create and schedule Microsoft Transaction Server-related Oracle transaction recovery.
This chapter contains these topics:
Scheduling Automatic Microsoft Transaction Server Transaction Recovery
Modifying Registry Values for Oracle Fail Safe Configurations
You must configure the Microsoft Transaction Server and Oracle Database environments after installing or migrating Oracle Services for Microsoft Transaction Server (OraMTS).
Configuration is not required on the Windows computer if a Microsoft Transaction Server is installed on a computer.
To configure the Microsoft Transaction Server, perform the following tasks on the computer where the Oracle Database is installed:
Run the oramtsadmin.sql script against the database to create the Microsoft Transaction Server administrative user account (the default username is mtssys).
Schedule automatic transaction recovery.
See "Scheduling Automatic Microsoft Transaction Server Transaction Recovery"
If you have an Oracle Fail Safe configuration, modify the registry values before or after running the oramtsadmin.sql script.
See "Modifying Registry Values for Oracle Fail Safe Configurations".
Distributed transaction capabilities are required to use Microsoft Transaction Server with Oracle database. Microsoft Transaction Server-related Oracle transactions become in-doubt transactions when any of the following fail:
Microsoft Transaction Server application
Network
An Oracle MTS Recovery Service resolves in-doubt transactions on the computer that started the failed transaction.
Typically, an Oracle MTS Recovery Service is automatically created and started with Oracle Services For Microsoft Transaction Server. However, for Oracle Database releases 11.2.0.3 through 11.2.0.x, depending on the options you choose during the install, Oracle MTS Recovery Service may be created, but not started at the end of the installation. In this case, it must be started manually.
Only one Oracle MTS Recovery Service can be installed for each computer. A scheduled recovery job on each Microsoft Transaction Server-enabled database permits the Oracle MTS Recovery Service to resolve in-doubt transactions.
The Oracle MTS Recovery Service resolves an in-doubt Microsoft Transaction Server transaction in the following order:
The DBMS recovery job detects an in-doubt MTS-related transaction.
The DBMS recovery job extracts the recovery service's endpoint address from the XID of the in-doubt transaction and requests the recovery service for the outcome of the MTS/MS DTC transaction.
The recovery service requests its MS DTC for transaction outcome.
The recovery service reports transaction outcome to the DBMS job process.
The DBMS recovery job commits or terminates the in-doubt transaction.
OraMTS uses server-based recovery to resolve in-doubt transactions originated by MSDTC. To do this, the OraMTS administrator must be able to access the Windows middle-tier node through UTL_HTTP. oramtsadmin.sql grants execute privileges on UTL_HTTP to the OraMTS administrator, as shown in "Configuring Automatic Transaction Recovery"
|
Note: Starting with Oracle version 11g, the DBA needs to create an access control list (ACL) as shown in "Creating an Access Control List (ACL)". |
For Oracle database version 11g and later, the DBA must create an access control list (ACL) that grants the OraMTS administrator the privilege to make out-bound HTTP connections. Example 3-1 demonstrates this:
Example 3-1 Creating an ACL List and Adding OraMTS Administrator to it
BEGIN
-- Create the new ACL, naming it "OraMTSadmin.xml", with a description.
-- This provides the OraMTS administrative user e.g. MTSADMIN user FOO
-- the privilege to connect
DBMS_NETWORK_ACL_ADMIN.CREATE_ACL('OraMTSadmin.xml',
'Allow usage to the UTL network packages',
'FOO', TRUE, 'connect');
-- Now grant privilege to resolve DNS names to the OraMTS administrative user
DBMS_NETWORK_ACL_ADMIN.ADD_PRIVILEGE('OraMTSadmin.xml' ,
'FOO', TRUE,'resolve');
-- Specify which hosts this ACL applies to, in this case we are allowing
-- access to all hosts. if one knew the list of all Windows middle-tier,
-- these could be added one by one.
DBMS_NETWORK_ACL_ADMIN.ASSIGN_ACL('OraMTSadmin.xml','*');
END;
Automatic transaction recovery is performed by scheduling a database job. A database job for in-doubt transactions must be scheduled for each database participating in Microsoft Transaction Server transactions.
Transaction recovery is configured by running the oramtsadmin.sql script, which triggers utl_oramts.sql and prvtoramts.plb scripts to create the PL/SQL package utl_oramts. The database view oramts_2pc_pending is also created to show in-doubt transactions related to Microsoft Transaction Server transactions.
The oramtsadmin.sql script:
Creates the Microsoft Transaction Server administrator user account.
Automatically schedules database jobs for transaction recovery every one minute.
When the database job is run, it checks for unresolved global transactions in the database that are related to Microsoft Transaction Server. Information in the transaction identifiers (XIDs) of the in-doubt transactions identifies the computer on which the transaction was started. The Oracle MTS Recovery Service on that computer resolves the transaction.
Schedules post-recovery cleanup every half hour.
Schedule automatic transaction recovery in the database by performing these tasks:
The JOB_QUEUE_PROCESSES initialization parameter specifies the maximum number of job slaves started on an instance.
To set and start up job-queue processes:
Ensure that you have SYSDBA privileges.
Go to the computer on which the Oracle Database is installed.
Start SQL*Plus:
C:\> sqlplus /NOLOG
Connect to the database as SYSDBA:
SQL> CONNECT / AS SYSDBA
Set the JOB_QUEUE_PROCESSES initialization parameter:
JOB_QUEUE_PROCESSES = 1
The default value for this parameter is 0. Set this parameter to a value greater than 1 if there are many destinations to which to propagate the messages.
Shut down the Oracle Database:
SQL> SHUTDOWN
Restart the Oracle Database:
SQL> STARTUP
Exit SQL*Plus:
SQL> EXIT
The oramtsadmin.sql script creates the Microsoft Transaction Server administrator user account with the default username mtssys. The Microsoft Transaction Server transaction recovery jobs run under the administrator user account.
The oramtsadmin.sql script runs the utl_oramts.sql script to grant the following privileges and roles to the administrator user account:
To create and schedule automatic transaction recovery:
Ensure that you have SYSDBA privileges.
Log on to the computer where the Oracle Database is installed.
Start SQL*Plus:
C:\> sqlplus /NOLOG
Connect to the database as SYSDBA:
SQL> CONNECT / AS SYSDBA
Run the oramtsadmin.sql script:
SQL> @ORACLE_BASE\ORACLE_HOME\oramts\admin\oramtsadmin.sql;
You are prompted for the Microsoft Transaction Server administrator username and password. You can accept the default username of mtssys and password of mtssys, or change them.
If you did change the password in step 5, you can change it using this script:
SQL> ALTER USER USERNAME IDENTIFIED BY new_password;
To change the username after completing this task, drop the user, rerun the oramtsadmin.sql script, and specify a different username when prompted.
Exit SQL*Plus:
SQL> EXIT
A single PL/SQL package, utl_oramts, is created in the Microsoft Transaction Server administrator's schema. utl_oramts exposes these public procedures and creates this view:
Use this procedure to view Microsoft Transaction Server in-doubt transactions in the database. This procedure uses the dbms_output package to display results.
Description This procedure requires SERVEROUTPUT set to ON.
SQL> SET SERVEROUTPUT ON SQL> EXECUTE utl_oramts.show_indoubt;
The following information appears:
========================================================= currently indoubt transactions ========================================================= formatid : 21255235 gtrid : C2229A505904974D81FB7316B147325900000000 bqual : 5BAB6A6B55CD294AA20335839110829C0100000000901944700050 local txid : 142.11.202 tx state : prepared protocol : HTTP endpoint : middletier-1@foo.com:2030 ========================================================= formatid : 21255235 gtrid : 259DF9C8DFC5574F8876F0DF4E15CCAD00000000 bqual : 2C8DCED5B9816244BA2B73CC013EEB870100000000901944700050 local txid : 2.18.185 tx state : prepared protocol : HTTP endpoint : middletier-2@foo.com:2030
This procedure is run by the transaction recovery job. An automatic database job is scheduled for utl_oramts.recover_automatic. When the job is run, it checks for unresolved global transactions in the database that are related to Microsoft Transaction Server. Information in the XIDs of the in-doubt transactions identifies the computer on which the transaction started. The Oracle MTS Recovery Service is contacted and resolves the transactions.
Use this procedure to request the transaction manager (MS DTC) to forget resolved transactions. This procedure is run by the post-recovery cleanup job.
The view oramts_2pc_pending is created by executing oramtsadmin.sql. oramts_2pc_pending shows in-doubt transactions in the database. This view consists of the following columns:
Formatid This is the formatid of the global transaction in the database.
global_transaction_id This is the transaction identifier of the Oracle global transaction corresponding to the Microsoft Transaction Server transaction. In fact, this is the globally unique identifier (GUID) of the Microsoft Transaction Server transaction.
branch_id This shows the branch identifier of the Oracle transaction. A single Microsoft Transaction Server transaction can have multiple Oracle global transactions. This depends on the number of Microsoft Transaction Server/COM+ components that span the same Microsoft Transaction Server transaction. All these transactions have the small global transaction identifier, but different branch identifiers.
local_tx_id A local Oracle transaction corresponds to each Microsoft Transaction Server transaction. This column shows the identifier corresponding to this local transaction.
state This shows the state of the transaction: pending, heuristically committed, heuristically terminated, and so on.
protocol This is the protocol that the transaction recovery job in the database uses to communicate with the Oracle MTS Recovery Service.
endpoint This is the endpoint of the Windows computer on which the Microsoft Transaction Server transaction originated. For HTTP connections, this translates to a hostname and port number.
To view Microsoft Transaction Server–related in-doubt transactions in the database, use SQL*Plus to query the view oramts_2pc_pending:
Start SQL*Plus with the Microsoft Transaction Server administrator user account:
C:\> sqlplus mtsadmin_user/ mtsadmin_password
Enter the following command:
SQL> SELECT * FROM oramts_2pc_pending;
This displays the computer on which the in-doubt transaction originated.
In typical configurations, the MS DTC and Oracle MTS Recovery Service run on the same computer. This ensures that the required information for transaction recovery is available to the Oracle-Microsoft Transaction Server integration layer.
In configurations where the Microsoft Transaction Server application is part of a Windows cluster (for example, the application can fail over to another node or host in the cluster), the MS DTC runs as a cluster-wide resource. All cluster nodes use a single instance of the MS DTC running on any cluster node.
If you have an Oracle Fail Safe configuration, make sure the following registry information is replicated on all nodes in the cluster participating in Microsoft Transaction Server transactions:
To modify registry values for Oracle Fail Safe configurations:
Go to the computer on which the MS DTC and Oracle MTS Recovery Service are installed.
Start the registry from the command prompt:
C:\> regedt32
The Registry Editor window appears.
Go to HKEY_LOCAL_MACHINE\Software\Oracle\OracleMTSRecoveryService.
Copy the registry information appearing here to all nodes in the cluster.
Reboot the computer on which you added the key.
This section describes new features of Oracle Database 11g Release 2 (11.2) and provides pointers to additional information.
The following sections describe the new features in Oracle Services for Microsoft Transaction Server.
Support for Promotable Single Phase Enlistment
Oracle database now allows all transactions to remain local until more than one database is brought into the transaction, at which point, they are promoted to distributed transactions.
Transparent Distributed Transactions on Real Applications Clusters
The database now redirects all the branches of a distributed transaction to a single Oracle RAC instance automatically.
Developer's Guide
11g Release 2 (11.2) for Microsoft Windows
E26104-01
October 2011
Oracle Services for Microsoft Transaction Server Developer's Guide, 11g Release 2 (11.2) for Microsoft Windows
E26104-01
Copyright © 1996, 2011, Oracle and/or its affiliates. All rights reserved.
Contributing Authors: Janis Greenberg, Patricia Huey, Mark Kennedy, Roza Leyderman, Janelle Simmons
Contributors: Alex Keh, Valarie Moore, Vivek Raja, Eric Wang, Yong Hu
This software and related documentation are provided under a license agreement containing restrictions on use and disclosure and are protected by intellectual property laws. Except as expressly permitted in your license agreement or allowed by law, you may not use, copy, reproduce, translate, broadcast, modify, license, transmit, distribute, exhibit, perform, publish, or display any part, in any form, or by any means. Reverse engineering, disassembly, or decompilation of this software, unless required by law for interoperability, is prohibited.
The information contained herein is subject to change without notice and is not warranted to be error-free. If you find any errors, please report them to us in writing.
If this is software or related documentation that is delivered to the U.S. Government or anyone licensing it on behalf of the U.S. Government, the following notice is applicable:
U.S. GOVERNMENT RIGHTS Programs, software, databases, and related documentation and technical data delivered to U.S. Government customers are "commercial computer software" or "commercial technical data" pursuant to the applicable Federal Acquisition Regulation and agency-specific supplemental regulations. As such, the use, duplication, disclosure, modification, and adaptation shall be subject to the restrictions and license terms set forth in the applicable Government contract, and, to the extent applicable by the terms of the Government contract, the additional rights set forth in FAR 52.227-19, Commercial Computer Software License (December 2007). Oracle USA, Inc., 500 Oracle Parkway, Redwood City, CA 94065.
This software or hardware is developed for general use in a variety of information management applications. It is not developed or intended for use in any inherently dangerous applications, including applications that may create a risk of personal injury. If you use this software or hardware in dangerous applications, then you shall be responsible to take all appropriate fail-safe, backup, redundancy, and other measures to ensure its safe use. Oracle Corporation and its affiliates disclaim any liability for any damages caused by use of this software or hardware in dangerous applications.
Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners.
This software and documentation may provide access to or information on content, products, and services from third parties. Oracle Corporation and its affiliates are not responsible for and expressly disclaim all warranties of any kind with respect to third-party content, products, and services. Oracle Corporation and its affiliates will not be responsible for any loss, costs, or damages incurred due to your access to or use of third-party content, products, or services.
Atomicity, Consistency, Isolation, and Durability (ACID)
ACID consists of the four primary attributes provided to any transaction by a transaction manager (also called a transaction manager).
component object model (COM)
A binary standard that enables objects to interact with other objects, regardless of the programming language in which each object was written.
distributed component object model (DCOM)
An extension of COM that enables objects to interact with other objects across a network.
data manipulation language
The category of SQL statements that query and update database data. Common DML statements are SELECT, INSERT, UPDATE, and DELETE.
JOB_QUEUE_PROCESSES
This initialization parameter specifies the maximum number of DBMS_JOB jobs and Oracle Scheduler (DBMS_SCHEDULER) jobs running concurrently on an instance. This parameter must be set to at least 1 to run Oracle Scheduler or DBMS_JOB jobs and to use database features that depend on these jobs
listener.ora
A listener configuration file that identifies the following for a listener:
Unique name
Protocol addresses on which it accepts connection requests
Services for which it is listening
Microsoft .NET
Microsoft .NET is a set of Microsoft software technologies used to connect information, people, systems, and devices through web services to each other and to larger applications over the Internet.
Microsoft application demo
An Oracle Call Interface (OCI) implementation of the Visual C++ Sample Bank package that ships with Microsoft Transaction Server on Windows.
Microsoft Distributed Transaction Coordinator (MS DTC)
The focal point of the transaction process is a component of Microsoft Transaction Server called Microsoft Distributed Transaction Coordinator (MS DTC).
Microsoft Transaction Server
A COM-based transaction processing system that runs on an Internet or network server.
mtssys
The default Microsoft Transaction Server administrator username. In releases prior to Oracle9i Database release 1 (9.0.1), this was the username for the OraMTS.
net service name
The name used by clients to identify an Oracle Net server and the specific system identifier (SID) or database for the Oracle Net connection. A net service name is mapped to a port number and protocol. A net service name is also known as a connect string, database alias, host string, or service name.
This also identifies the specific SID or database to which the connection is attaching, and not just the Oracle Net server.
Oracle Call Interface (OCI)
An application programming interface that enables you to manipulate data and schemas in a database. You compile and link an OCI program in the same way that you compile and link a nondatabase application. There is no requirement for a separate preprocessing or precompilation step.
Oracle Data Provider for .NET (ODP.NET)
Oracle Data Provider for .NET (ODP.NET) features optimized data access to the Oracle Database from a .NET environment. ODP.NET includes support for connection pooling, PL/SQL, LOBs, RefCursors, globalization/localization, proxy user authentication/ parameter array binding, named parameters, and safe type mapping between Oracle types and .NET types.
Oracle Fail Safe
Ensures that if a failure occurs on one cluster node, then the databases and applications running on that node fail over (move) automatically and quickly to a surviving node.
Oracle MTS Recovery Service
The Oracle MTS Recovery Service resolves in-doubt transactions on the computer that started the failed transaction. A scheduled recovery job for each Microsoft Transaction Server-enabled database lets the Oracle MTS Recovery Service resolve in-doubt transactions.
Oracle Objects for OLE (OO4O)
Oracle Objects for OLE (OO4O) is a COM-based database connectivity tool that combines seamless and optimized access to Oracle Database instances with easy to use interfaces.
Oracle Open Database Connectivity (ODBC) Driver
Oracle ODBC Driver provides a standard interface that allows one application to access many different data sources. The application's source code does not have to be recompiled for each data source. A database driver links the application to a specific data source. A database driver is a dynamic link library that an application can invoke on demand to gain access to a particular data source. Therefore, the application can access any data source for which a database driver exists.
Oracle Provider for OLE DB
Interfaces that offer high performance and efficient access to Oracle data by applications, compilers, and other database components.
Oracle Services for Microsoft Transaction Server (OraMTS)
A component that provides full integration of the Oracle Database with Microsoft Transaction Server. This component enables you to develop and deploy COM-based applications using Microsoft Transaction Server.
Optimal Flexible Architecture (OFA)
A set of file naming and placement guidelines for Oracle software and databases.
resource manager (RM)
Microsoft Transaction Server enlists the database to act as a resource manager (RM) in the transaction process.
SYSDBA
A special database administration role that contains all system privileges with the ADMIN OPTION and the SYSOPER system privilege. SYSDBA also permits CREATE DATABASE actions and time-based recovery.
SYSOPER
A special database administration role that permits a database administrator to perform STARTUP, SHUTDOWN, ALTER DATABASE OPEN/MOUNT, ALTER DATABASE BACKUP, ARCHIVE LOG, and RECOVER, and includes the RESTRICTED SESSION privilege.
tnsnames.ora
A file that contains connect descriptors mapped to net service names. The file can be maintained centrally or locally for use by all or individual clients.
This manual explains how to install, configure, use, and administer Oracle Services for Microsoft Transaction Server that apply to operating systems. It covers the features of Oracle Database software that apply to the Windows 2000, Windows XP, and Windows Server 2003 operating systems.
This preface contains these topics:
This guide is intended for anyone who performs the following tasks:
Uses component object model (COM) components with Microsoft Transaction Server
Registers COM components as transactional and has Microsoft Transaction Server control the transaction
Uses client-side connection pooling in Microsoft Transaction Server
Uses .NET applications with Oracle Services for Microsoft Transaction Server to access Oracle Database instances.
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.
For more information, see these Oracle resources:
For information about Oracle error messages, see Oracle Database Error Messages. Oracle error message documentation is available only in HTML. If you only have access to the Oracle Documentation CD, you can browse the error messages by range. Once you find the specific range, use your browser's "find in page" feature to locate the specific message. When connected to the Internet, you can search for a specific error message using the error message search feature of the Oracle online documentation.
Many of the examples in this book use the sample schemas of the seed database, which is installed by default when you install Oracle. Refer to Oracle Database Sample Schemas for information on how these schemas were created and how you can use them yourself.
To download free release notes, installation documentation, white papers, or other collateral, please visit the Oracle Technology Network (OTN). You must register online before using OTN; registration is free and can be done at
http://www.oracle.com/technology/membership/
If you already have a username and password for OTN, then you can go directly to the documentation section of the OTN Web site at
http://www.oracle.com/technology/documentation/
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. |
This chapter describes installation and migration requirements for the Microsoft Transaction Server and Oracle Database environment.
This chapter contains these topics:
You can install OraMTS by choosing the Custom installation type when you install Oracle Database.
This section describes the Oracle and non-Oracle products you must install for OraMTS. Additional installation requirements include:
Only one Oracle MTS Recovery Service exists on each computer.
For Oracle Data Provider for .NET (ODP.NET) cluster configurations (or any failover configuration), install Microsoft Transaction Server on the node running the Microsoft Distributed Transaction Coordinator (MS DTC) component. This ensures that the Oracle MTS Recovery Service migrates with the client application during failover. You can configure this when scheduling recovery transactions.
The Windows computer where Microsoft Transaction Server is installed has the following product requirements:
A data access driver that uses Oracle Services for MTS, such as:
|
Notes:
|
This illustration describes component integration in a transaction. The role of each component is described in the text immediately following the illustration.
PK\8 3 PK */A OEBPS/img_text/ntmts012.htmSThis illustration shows how, through Oracle Net, Microsoft Transaction Server-based COM components (not shown) can acquire connections to both dedicated and shared Oracle servers of database A. These components then attempt to perform distributed updates (data manipulation language) on database B using database links from database A to database B. While the distributed updates from the shared servers succeed, those from dedicated servers fail.
PKgX S PK */A OEBPS/perftune.htm2>This chapter provides Microsoft Transaction Server performance tuning information.
This chapter contains these topics:
Optimizing the programming methods of your application improves its performance. For example, placing all code for a given transaction into one component object model (COM) component means you do not mark that component as transactional. This eliminates the overhead of going through Microsoft Transaction Server. You can subsequently use the Oracle commit or rollback functions to control that transaction in the component. If you are using the Oracle Call Interface (OCI), you can still use ORAMTSSvcGet(), but you can also use the ORAMTS_CFLG_NOIMPLICIT flag. If you are updating across two or more Oracle Database instances, use database links and connect to one database from the COM component.
|
See Also: "OCI Integration with Microsoft Transaction Server" for more information on usingORAMTSSvcGet() |
When a .NET or COM component ends a session with the Oracle Database, the connection does not immediately terminate. Instead, it remains idle in a connection pool, where it is available for reuse by another component attempting a new connection to the Oracle Database.
The idle period during which a connection is reusable reduces the resource costs associated with opening a new connection. The amount of time that the connection remains idle and available in the connection pool is determined by several registry parameter settings. You can modify these parameters on the computers on which the client Microsoft Transaction Server components are installed, in the file HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE\HOMEID:
ORAMTS_CONN_POOL_TIMEOUT The time, in seconds, that the connection remains idle and available for reuse in the client side connection pool, before timing out and being released. The default value of this parameter is 120 seconds.
ORAMTS_SESS_TXNTIMETOLIVE The time, in seconds, that the connection established using OraMTSSvcGet() remains alive in the client side connection pool after being released by an OraMTSSvcRel() call. The sum of the ORAMTS_CONN_POOL_TIMEOUT and ORAMTS_NET_CACHE_TIMEOUT values determines the actual time before a connection terminates completely. The default value of this parameter is 120 seconds.
ORAMTS_NET_CACHE_TIMEOUT The resource dispenser implemented inside Oracle Services for Microsoft Transaction Server establishes pooled connections to Oracle databases. When these connections are no longer in use, the user sessions are disconnected after the timeout specified by ORAMTS_CONN_POOL_TIMEOUT. However, the underlying Oracle Net connections are cached for the period specified by this parameter. After this time, expressed in milliseconds, a cached Oracle Net connection to the database will be terminated. The default value of this parameter is 120000 milliseconds. Oracle recommends setting this parameter to a higher value than the value for ORAMTS_CONN_POOL_TIMEOUT. The sum of the time periods specified for ORAMTS_CONN_POOL_TIMEOUT and ORAMTS_NET_CACHE_TIMEOUT determines the actual time before a connection terminates completely.
ORAMTS_NET_CACHE_MAXFREE The maximum number of free server connections that should be maintained in the client-side connection pool at a given time. The default value of this parameter is 5.
ORAMTS_OSCREDS_MATCH_LEVEL The level of Windows security checking implemented when the OS_ROLES initialization parameter in the init.ora file is true.
When a user establishes a connection to the Oracle Database using the CONNECT command, the Windows username is associated with specific database roles and privileges. When the user disconnects, this connection becomes idle and available in the pool. When another user enters the CONNECT command, if the Windows username is identical to the one used by the first user, the second user can receive the same database roles and privileges as the first user. This is a considerable security concern, especially if the second user possesses only the CREATE SESSION and RESOURCE database roles but receives the DBA privileges of the first user.
By default, the ORAMTS_OSCREDS_MATCH_LEVEL parameter value is OS_AUTH_LOGIN, and Windows security checking is performed only if the username and password are NULL.
The most secure setting for this parameter is ALWAYS, which ensures that Windows security checking is performed in all cases, and takes care of possible security breaches due to identical non-null Window usernames.
Because Windows security checking is a resource-intensive operation, you may wish to set the value of this parameter to NEVER. However, if you know that OS_ROLES is true, or if you use operating system-authenticated connections, you should avoid this option.
If transaction requests are timing out before completing, the transaction timeout parameter may be set too low. Increase the transaction timeout parameter to ensure that transactions have enough time to complete.
To increase the transaction timeout parameter:
Go to the Windows computer on which Microsoft Transaction Server is installed.
From the Start menu, select Programs, then Administrative Tools, then Component Services.
The Component Services window appears.
Double-click Console Root in the Component Services window so its tree structure expands.
Double-click Component Services.
Double-click Computers.
Right-click My Computer.
A menu appears with several options.
Choose Properties.
The My Computer Properties dialog box appears.
Choose the Options tab.
Enter a value in the Transaction Timeout field and click OK.
The transaction timeout value is increased. For most environments, 60 seconds may be enough. However, if the transaction is competing with numerous concurrent transactions, this value may be too low.
You may need to modify several initialization parameters to use the Oracle Database with Microsoft Transaction Server. The values you should set these parameters to are based on the database workload environment.
To verify initialization parameter file values, follow these steps:
Ensure that you have SYSDBA privileges.
Go to the computer on which the Oracle Database is installed.
Start SQL*Plus:
C:\> sqlplus /NOLOG
Connect to the database as SYSDBA:
SQL> CONNECT / AS SYSDBA
Check the value for the SESSIONS parameter:
SQL> SHOW PARAMETER SESSIONS
Check the value for the PROCESSES parameter:
SQL> SHOW PARAMETER PROCESSES
The current settings for both SESSIONS and PROCESS parameters are typically appropriate for running the Microsoft application demo. For creating and deploying .NET or COM-based applications, the values for these parameters depend on the database environment's anticipated workload. For example, if you anticipate 100 concurrent connections to the Oracle Database, consider setting both values to 200 to accommodate a possible system overload. Ensure that you do not set these parameters too high, because they are resource-intensive.
Set the following initialization parameters to at least these values:
SESSIONS = 200 (or larger if anticipating heavier loads)
PROCESSES = 200 (or larger if anticipating heavier loads)
Shut down the Oracle Database:
SQL> SHUTDOWN
Restart the Oracle Database:
SQL> STARTUP
Exit SQL*Plus:
SQL> EXIT
Use the registry variable ORAMTS_ABORT_MODE to control whether a new connection always performs an abort or whether the originally enlisted connection can be used to perform the abort, that is, whether the abort is synchronous or asynchronous.
By default, the originally enlisted connection performs transaction aborts (whenever possible).
Registry variable: ORAMTS_ABORT_MODE
Values:
ORAMTS_ABORT_MODE_NEW_CONN_ONLY: Results in asynchronous aborts. A new connection to the database is opened for performing transaction aborts.
Any other value implies the default behavior.
The Microsoft Distributed Transaction Coordinator (MS DTC) must be running to enable communication with Oracle Services for Microsoft Transaction Server.
To start MS DTC, follow these steps:
On the computer where Microsoft Transaction Server is installed, from the Start menu, choose Programs, then Administrative Tools, then Component Services.
The Component Services window appears.
In the Component Services Window, expand Component Services under the Console Root.
Expand Computers under Component Services.
Right-click My Computer.
A menu with several options appears.
Choose Start MSDTC.
MS DTC starts.
This chapter describes how to program with Microsoft Transaction Server and an Oracle Database.
This chapter contains these topics:
OraMTS also provides integration with OO4O, Oracle Provider for OLE DB, and Oracle Data Provider for .NET.
|
See Also:
|
The focal point of the transaction process is a component of Microsoft Transaction Server called Microsoft Distributed Transaction Coordinator (MS DTC). When a client computer starts a business method on a transactional component, Microsoft Transaction Server begins a transaction coordinated by the MS DTC. The Oracle connection pooling layer enables the database to act as a resource manager (RM) in the MS DTC-coordinated transaction. Figure 4-1 illustrates this transactional model.
Figure 4-1 Component Integration in a Transaction
Client Computer The client computer activates the application components on the MTS Application Server through a Web browser or through the component object model (COM) /distributed component object model (DCOM).
MTS Application Server The MTS application server consists of the services that the Windows operating service provides to host transactional application components that a client computer can activate, either indirectly through a Web browser or directly through the component object model (COM) /distributed component object model (DCOM). In response to client requests, the application server invokes the COM components. The invocations are performed within the scope of transactions where required
Transactional Application Logic COM Components Three primary responsibilities:
Embed the business logic. If a component is transactional, Microsoft Transaction Server starts a transaction for every method invocation on that component.
Acquire pooled connections to a Oracle Database through the Oracle resource dispenser and Oracle Call Interface (OCI), Oracle Open Database Connectivity (ODBC) Driver, Oracle Provider for OLE DB, or Oracle Objects for OLE (OO4O).
Decide the outcome of the operation by notifying Microsoft Transaction Server of its decision to commit or terminate the changes to all RMs.
Oracle ODBC Driver, OO4O, Oracle Provider for OLE DB, and OCI Two primary responsibilities:
Obtain a service context to the Oracle Database through the OCI connection pooling component.
Provide connection pooling resources, if necessary (through Oracle Provider for OLE DB or Oracle ODBC Driver). The Oracle ODBC Driver provides pooled ODBC connections. Oracle Provider for OLE DB provides pooled data source objects. OO4O uses the OCI connection pool.
OCI Connection Pool Three primary responsibilities:
Enlists the RM (Oracle Database) in the component's Microsoft Transaction Server transaction.
Starts an Oracle global transaction corresponding to the Microsoft Transaction Server transaction of which the component is a part.
Acts as a resource dispenser to perform client-side connection pooling.
Oracle Net Provides connectivity in distributed, heterogeneous computing environments.
Oracle MTS Recovery Service Recovers in-doubt Oracle transactions that originated from the host computer and are related to the Microsoft Transaction Server.
Database Recovery Job Detects in-doubt DTC transactions. This job extracts the recovery service's endpoint address in the in-doubt transaction's XID and then requests the outcome of the Microsoft DTC transaction from the recovery service. Ultimately, the job will commit or terminate the in-doubt transaction when it receives the transaction's outcome.
Microsoft DTC Microsoft Distributed Transaction Coordinator is part of Microsoft Transaction Server and has two primary responsibilities:
Commits and terminates transactions using the two-phase commit protocol.
Monitors transactions that require recovery. Multiple MS DTCs can be involved in a single transaction. When a transactional Microsoft Transaction Server component on computer A invokes another transactional Microsoft Transaction Server component on computer B, a connection is opened between the MS DTC on computer A and the MS DTC on computer B. When the root MS DTC commits or terminates a transaction, it sends the request through all involved MS DTCs. The transaction request is then passed to the OCI connection pooling/Microsoft Transaction Server integration, which sends it to the database.
Oracle Database Acts as an RM for Microsoft Transaction Server. This is the database on which the client transaction request is performed.
OCI connection pooling is used to coordinate a transaction in nearly all application programming interfaces. This sections describes how transactions are registered and how OCI connection pooling coordinates them.
Application components that run in the Microsoft Transaction Server environment are created as dynamic link libraries (DLLs). Application components are registered with Microsoft Transaction Server using the Microsoft Transaction Server Explorer graphical user interface (GUI) tool.
When you register the application component, you mark it as one of the following types:
Requires a Transaction The component must run in a transaction. If the transaction does not currently exist, Microsoft Transaction Server automatically creates a new transaction for each method invocation on the component.
Supports a Transaction The component can run within the client's transaction. When a new component is created, its context inherits the transaction from the context of the invoking client. If the client does not have a transaction, the new context is also created without one.
Requires a New Transaction The component must run within its own transaction. Microsoft Transaction Server automatically creates a new transaction for each method invocation on the component.
Does Not Support Transactions The component does not run within a transaction. Each method invocation on the component is performed without a surrounding transaction, regardless of whether the invoking client includes a transaction.
How you register an application component determines if it runs in a Microsoft Transaction Server-coordinated transaction.
If the application component runs in a Microsoft Transaction Server-coordinated transaction, the OCI connection pooling is always used and Microsoft Transaction Server and its MS DTC component coordinate the creation, startup, management, and commitment phases of the transaction. Microsoft Transaction Server ensures that all changes made by the component are committed if the transaction succeeds, or are terminated if the transaction fails.
If the application component does not run in a Microsoft Transaction Server-coordinated transaction, the component runs in a Microsoft Transaction Server environment, but the databases that it accesses may or may not take part in MS DTC-coordinated transactions. If the transaction is not MS DTC-coordinated, the client application must create, start, manage, and commit the transaction. OCI connection pooling may be used, depending upon the interface accessing the database (such as Oracle Provider for OLE DB, Oracle ODBC Driver, OO4O, or others).
This section describes how OCI connection pooling, Microsoft Transaction Server, and MS DTC operate with application components in a Microsoft Transaction Server-coordinated transaction environment.
The client API (one of Oracle ODBC Driver, OCI, OO4O, ODP.NET or Oracle Provider for OLE DB) calls OCI function OraMTSSvcGet() to obtain a service context from the OCI connection pooling component.
The OCI connection pooling component enlists the transaction that will be coordinated by the MS DTC component of Microsoft Transaction Server.
The OCI service and environment handles are returned to client applications.
The client application:
Performs the database operations.
Calls OCI function OraMTSSvcRel() to release the OCI pooling connection obtained at the beginning of the transaction.
Calls SetComplete (to commit database operations) or SetAbort (to terminate database operations) on the Microsoft Transaction Server context object associated with the component.
MS DTC performs the two-phase commit protocol to prepare and commit or to terminate the transaction. This notifies the OCI connection pooling component and ends the transaction.
OCI connection pooling is notified and performs the necessary steps to complete phase one, the prepare phase, and phase two, the commit or terminate phase.
This section describes how OCI connection pooling, Microsoft Transaction Server, and MS DTC operate with application components not running in a Microsoft Transaction Server-coordinated transaction, but using MS DTC.
The client application starts an MS DTC transaction and connects to the Oracle Database. The connection protocol follows one of the following scenarios:
Nonpooled OCI connections are obtained through OCI logon calls such as OCIServerAttach() and OCISessionBegin(). For these connections, the application calls OraMTSEnlCtxGet() to associate the OCI service context with a Microsoft Transaction Server enlistment context.
A connection pool is obtained by calling OraMTSSvcGet(..,..,ORAMTS_CFLG_NOIMPLICIT).
The client handles the context in one of the following scenarios:
For nonpooled connections, the client application passes in the enlistment context to OraMTSJoinTxn().
For pooled connections, the client application passes the OCI service context into OraMTSSvcEnlist().
The OCI connection pooling component enlists the connection, either pooled or nonpooled, in the transaction coordinated by the MS DTC component of Microsoft Transaction Server.
The client application then:
Performs database operations.
Calls OraMTSSvcEnlist() with a NULL transaction reference to de-enlist from an MS DTC coordinated transaction.
For nonpooled connections, OraMTSTxnJoin() is invoked with a NULL transaction reference to perform the de-enlistment.
Calls OraMTSSvcRel() to release a pooled connection back to the pool.
For nonpooled connections, the client calls OraMTSEnlCtxRel() to release the enlistment context and then logs off the database.
Calls the commit or terminate method on the MS DTC transaction object, such as pTransaction->Commit() or pTransaction->Abort().
MS DTC performs the two-phase commit protocol to commit the transaction.
OCI connection pooling is notified and performs the necessary steps to complete phase one, the prepare phase, and phase two, the commit or terminate phase.
Example 4-1 illustrates how you can integrate the MTS sever with OCI. The only change in code you must make involves obtaining and releasing the OCI service context handle. Both OCI service context handle and environment handle are acquired when you obtain a pooled OCI connection to the database by calling OraMTSSvcGet(). Include the oramts.h header and link with the oramts.lib library. When you are finished, call OCI function OraMTSSvcRel() to release the service context handle and environment handle. Using OraMTSSvcGet() enables you to receive connection pooling and implicit transaction support if you registered the application component to run in a Microsoft Transaction Server transaction.
Ensure that for each process, you call OCIInitialize at least once before executing any other OCI calls. This initializes the OCI process environment. In addition, you must pass it the OCI_THREADED flag. If you are using Microsoft Internet Information Server (IIS) and the components are being called as in-process libraries, then OCIInitialize is already called for you. The registry key ORAMTS_OCI_OBJ_MODE has been added. Set the value to 1 to initialize OCI in Object mode; otherwise OCI will initialize in the threaded mode.
Example 4-1 Integration of MTS and OCI
#include <oci.h>
#include <oramts.h>
#include <xolehlp.h>
// other MTS relevant includes ...
// prototype for the error handler.
BOOL Chekerr(sword swOCIStat, OCIError *OCIErrh);
// MTS component method
HRESULT OCITestMethod()
{
IObjectContext *pObjectContext = NULL;
OCIEnv *myenvh = NULL;
OCISvcCtx *mysvch = NULL;
OCIError *myerrh = NULL;
OCIStnt *mystmh = NULL;
DWORD dwStat;
HRESULT hRes = S_OK;
sword swOCIStat;
BOOL bCommit = FALSE;
char *lpzStmt = "UPDATE EMP SET SAL = SAL + 1000";
// Initialize the OCI environment first -- request OCI_THREADED
OCIInitialize(OCI_THREADED, (dvoid*)NULL,NULL,NULL,NULL);
// attempt to get a connection to the database through the resource dispenser
OraMTSSvcGet(
"hr","hr_password","finprod_db",&mysvch, &myenvh, ORAMTS_CFLG_ALLDEFAULT);
// validate return status
if(dwStat != ORAMTS_ERR_NOERROR)
{
printf("error: failed to obtain a connection to the database - %ld",
dwStat);
goto cleanup;
}
// successful logon and enlistment in the MTS transaction. allocate statement
// handles and other handles using the OCI environment handle myenvh ....
swOCIStat = OCIHandleAlloc(myenvh, (void *)&myerrh,OCI_HTYPE_ERROR, 0 , NULL);
if (Checkerr(swOCIStat, myerrh)) goto cleanup;
swOCIStat = OCIHandleAlloc(myenvh, (dvoid *)&mystmh,OCI_HTYPE_STMT, 0,NULL);
if (Checkerr(swOCIStat, myerrh)) goto cleanup;
// prepare a DML statement
OCIStmtPrepare(mystmh, myerrh, lpzStmt, lstrlen(lpzStmt), OCI_NTV_SYNTAX,
OCI_DEFAULT)
Checkerr(swOCIStat, myerrh);
// execute the statement -- ensure that AUTOCOMMIT is not requested.
OCIStmtExecute(mysvch, mystmh, myerrh, 1, 0, NULL, NULL, OCI_DEFAULT);
if (Checkerr(swOCIStat, myerrh)) goto cleanup;
// all's well so far choose to go for a commit
bCommit = TRUE;
cleanup:
if (mystmh) OCIHandleFree((void*)mystmh, OCI_HTYPE_STMT);
if (myerrh OCIHandleFree((void*)myerrh, OCI_HTYPE_ERROR);
if (mysvch) OraMTSSvcRel(mysvch);
if (bCommit)
pObjectContext->SetComplete();
else
pObjectContext->Abort();
return(bCommit ? S_OK : E_FAIL);
}
There are several scenarios for integrating COM components. COM applications that are not hosted by the Microsoft Transaction Server environment, also known as standalone applications, cannot use declarative transactions through the Microsoft Transaction Server Explorer Microsoft Management Console, but they can use the last three of the scenario described.
COM components that are running in an MTS-coordinated transactions use OCI connection pooling to implicitly enlist the database in a transaction. The following pseudo-code listing illustrates the use of OCI functions:
OCIInitialize(OCI_THREADED, ...) OraMTSSvcGet(..., &OCISvc, ..., ORAMTS_CFLAG_ALLDEFAULT) ... OraMTSSvcRel(OCISvc)
COM components that are marked as non-transactional and running in an MTS-coordinated transaction use OCI connection pooling do not enlist the database in a transaction. The following pseudo-code listing illustrates the use of OCI functions:
OCIInitialize(OCI_THREADED, ...) OraMTSSvcGet(..., &OCISvc, ..., ORAMTS_CFLAG_NOIMPLICIT) ... OraMTSSvcRel(OCISvc)
COM components that are not running in an MTS-coordinated transaction use MS DTC with OCI connection pooling to explicitly enlist the database in a transaction. The following pseudo-code listing illustrates the use of OCI functions:
OCIInitialize(OCI_THREADED, ...) DTCGetTransactionManager(...) BeginTransaction(..., &transaction) OraMTSSvcGet(..., &OCISvc, ..., ORAMTS_CFLAG_NOIMPLICIT) OraMTSSvcEnlist(OCISvc, ..., transaction, ...) ... OraMTSvcEnlist(OCISvc, ..., NULL, ...) OraMTSSvcRel(OCISvc)
COM components that are not running in an MTS-coordinated transaction use MS DTC with a non-pooling OCI connection to explicitly enlist the database in a transaction. The following pseudo-code listing illustrates the use of OCI functions:
OCIInitialize(OCI_THREADED, ...) OCI to get connected OraMTSEnlCtxGET DTCGetTransactionManager(...) BeginTransaction(..., &transaction) OraMTSJoinTxn (OCISvc, ..., transaction, ...) ... OraMTSJoinTxn ... OraMTSEnlCtxRel() OCI to logoff
This section details the OCI functions discussed earlier in this section. Table 4-1 summarizes these functions.
Table 4-1 Summary of OCI Functions for Integrating MTS and Oracle Database
| OCI Function | Summary |
|---|---|
|
|
Obtains a pooled connection from the OCI connection pool. |
|
|
Releases a pooled OCI connection, OCI service context, back to the connection pool. |
|
|
Enlists or de-enlists an OCI connection in a transaction coordinated by MS DTC. |
|
|
Enlists an OCI connection or service context in an MS DTC transaction. |
|
|
Creates an enlistment context for a nonpooled OCI connection. |
|
|
Eliminates a previously set up enlistment context for a nonpooled OCI connection. |
|
|
Enlists a nonpooled OCI connection in an MS DTC transaction. |
|
|
Tests if you are running inside a Microsoft Transaction Server-started transaction. |
|
|
Retrieves the OCI error code and message text. |
Obtains a pooled connection, also known as an OCI service context, from the OCI connection pool. The pooled connection includes an OCI service context handle and an OCI environment handle.
DWORD OraMTSSvcGet(
text* lpUname,
text* lpPsswd,
text* lpDbnam,
OCISvcCtx** pOCISvc,
OCIEnv** pOCIEnv,
ub4 dwConFlgs);
Table 4-2 OraMTSSvcGet() Parameters
| Parameter | IN/OUT | Description |
|---|---|---|
|
|
IN |
Username for connecting to the Oracle Database |
|
|
IN |
Password for the username |
|
|
IN |
The net service name for connecting to the database (created with Oracle Net Manager or Oracle Net Configuration Assistant) |
|
|
OUT |
Pointer to the OCI service context handle |
|
|
OUT |
Pointer to the OCI environment handle |
|
|
IN |
Connection flags. Possible values are:
|
Returns ORAMTSERR_NOERROR upon successful acquisition of an OCI pooling connection (OCI service context).
Usage Notes
OraMTSSvcGet() returns a pooled OCI connection to the caller, enabling a database transaction using OCI to begin. Use OraMTSSvcGet() to implicitly enlist the OCI connection in a transaction coordinated by Microsoft Transaction Server. In this type of transaction, Microsoft Transaction Server controls the creation, startup, management, and commitment phases of the transaction through its MS DTC component.
OraMTSSvcGet() also provides connection pooling without enlisting the Oracle Database in a Microsoft Transaction Server transaction. This is done by setting OraMTSSvcGet() as follows:
OraMTSSvcGet(...,ORAMTS_CFLG_NOIMPLICIT)
In all cases where OraMTSSvcGet() is used, you must always use OraMTSSvcRel() to release the connection when finished.
Use the flags ORAMTS_CFLG_SYSDBALOGN and ORAMTS_CFLG_SYSOPRLOGN when connecting as SYSDBA and SYSOPER, respectively.
To obtain a nonenlisted connection using the hr/hr_password account, call OraMTSSvcGet() as follows:
OraMTSSvcGet("hr", "hr_password", "oracle", &OCISvc, &OCIEnv, ORAMTS_CFLG_ALLDEFAULT | ORAMTS_CFLG_NOIMPLICIT);
OraMTSSvcGet() does not support placing the username (lpUname), password (lpPsswd), and net service name syntax (lpDbname) together in the username argument (for example, hr/hr_password@prod_fin). Instead, the caller must fill in lpUname, lpPsswd, and lpDbname separately (as shown in the previous syntax example). Calling OraMTSSvcGet() with the username and password as NULL strings uses external authentication (operating system authentication) for the connection.
Releases a pooled OCI connection, OCI service context, back to the connection pool. Use this function to release connections that were acquired with OraMTSSvcGet().
DWORD OraMTSSvcRel(OCISvcCtx* OCISvc);
Parameters
Table 4-3 OraMTSSvcRel() Parameters
| Parameter | IN/OUT | Description |
|---|---|---|
|
|
IN |
OCI service context for a pooled connection |
Returns ORAMTSERR_NOERROR upon successful release of a pooled OCI connection.
Usage Notes
An OCI pooled connection obtained through a previous call to OraMTSSvcGet() is released back to the connection pool. Once released back to the connection pool, the OCI service context, its environment handle, and all child handles are invalid.
A nontransactional client component must explicitly call OCITransCommit() or OCITransAbort() prior to releasing a connection obtained through OraMTSSvcGet(..., ...,ORAMTS_CFLG_ALLDEFAULT) back to the pool. Otherwise, all changes made in that session are rolled back. A transaction component uses the SetComplete or SetAbort methods on its Microsoft Transaction Server object context.
Components that have called OraMTSSvcGet(..., ...,ORAMTS_CFLG_NOIMPLICIT) to obtain a connection resource must first de-enlist the resource if enlisted. If the connection was enlisted explicitly, pTransaction->Commit() or pTransaction->Abort() must be called. Otherwise, OCITransCommit() or OCITransAbort() must be called before releasing the connection back to the pool.
Enlists or de-enlists an OCI connection in a transaction coordinated by MS DTC. Use this call to explicitly enlist pooled connections. Nonpooled connections must enlist with OraMTSJoinTxn().
DWORD OraMTSSvcEnlist(
OCISvcCtx* OCISvc,
OCIError* OCIErr,
void* lpTrans,
unsigned dwFlags);
Table 4-4 OraMTSSvcEnlist() Parameters
Returns ORAMTSERR_NOERROR on success.
Use this call to explicitly enlist or de-enlist a pooled connection. For enlisting and de-enlisting nonpooled connections, use OraMTSSvcRel().
OraMTSSvcEnlist() enlists (or de-enlists) pooled OCI connections obtained previously through OraMTSSvcGet() with the ORAMTS_CFLG_NOIMPLICIT flag and not yet released with OraMTSSvcRel(). The pooled OCI connections must be explicitly enlistable. When the transaction is complete, you must de-enlist OraMTSSvcEnlist(), passing NULL as the transaction pointer as follows:
OraMTSSvcEnlist (OCISvc, OCIErr, NULL, ORAMTS_ENFLG_DEFAULT)
You must use OraMTSSvcRel() to release the connection when done.
Callers must allocate a connection, enlist the connection, perform work, de-enlist the connection, release the connection, and then attempt to commit or terminate.
Enlists an OCI connection or service context in an MS DTC transaction. Use this call only to explicitly enlist pooled connections. Nonpooled connections must enlist with OraMTSJoinTxn().
DWORD OraMTSSvcEnlistEx(
OCISvcCtx* OCISvc,
OCIError* OCIErr,
void* lpTrans,
unsigned dwFlags,
char* lpDBName);
Parameters
Table 4-5 OraMTSSvcEnlistEx() Parameters
Returns ORAMTSERR_ILLEGAL_OPER.
Use OraMTSSvcEnlistEx() for pooled connections or OraMTSJoinTxn() for nonpooled connections.
Creates an enlistment context for a nonpooled OCI connection.
Syntax
DWORD OraMTSEnlCtxGet(
text* lpUname,
text* lpPsswd,
text* lpDbnam,
OCISvcCtx* pOCISvc,
OCIError* pOCIErr,
ub4 dwFlags,
void** pCtxt);
Table 4-6 OraMTSEnlCtxGet() Parameters
| Parameter | IN/OUT | Description |
|---|---|---|
|
|
|
Username for connecting to the Oracle Database |
|
|
|
Password for connecting to the Oracle Database |
|
|
|
Net service name for connecting to a database |
|
|
|
OCI service context for a nonpooled connection |
|
|
|
OCI error handle |
|
|
|
Enlistment flags. The only value currently permitted is |
|
|
|
Enlistment context to be created |
Returns
Returns ORAMTSERR_NOERROR on success.
Usage Notes
This call sets up an enlistment context for a nonpooled connection. This call must be started just after the caller establishes the OCI connection to the database. Once created, this context can be passed into OraMTSJoinTxn() calls. Prior to deleting the OCI connection, OraMTSEnlCtxRel() must be called to delete the enlistment context.
Callers must:
Allocate a nonpooled connection through OCI.
Create an enlistment context by calling OraMTSEnlCtxGet().
Enlist the connection by calling OraMTSJoinTxn().
Perform database work.
De-enlist the connection by calling OraMTSJoinTxn() with a NULL transaction pointer.
Attempt to commit or terminate work.
Release the enlistment context by calling OraMTSEnlCtxRel().
Release the nonpooled OCI connection and delete its associated OCI environment handle.
Eliminates a previously set up enlistment context for a nonpooled OCI connection.
DWORD OraMTSEnlCtxRel(void* pCtxt);
Table 4-7 OraMTSEnlCtxRel() Parameters
| Parameter | IN/OUT | Description |
|---|---|---|
|
|
IN |
Enlistment context to eliminate |
Returns ORAMTSERR_NOERROR on success.
Usage Notes
Before dropping a nonpooled OCI connection, a client must call OraMTSEnlCtxRel() to eliminate any enlistment context it may have created for that connection. The enlistment context can maintain OCI handles allocated off the connection's OCI environment handle. This makes it imperative that the environment handle is not deleted for the associated enlistment context.
Enlists a nonpooled OCI connection in an MS DTC transaction.
DWORD OraMTSJoinTxn(void* pCtxt,
void* pTrans);
Parameters
Table 4-8 OraMTSJoinTxn() Parameters
| Parameter | IN | Description |
|---|---|---|
|
|
|
Enlistment context for the OCI connection |
|
|
|
Reference to the MS DTC transaction object |
Returns ORAMTSERR_NOERROR on success.
Usage Notes
Clients use this call with nonpooled OCI connections to enlist connections in MS DTC-coordinated transactions. The client passes in the wide reference to the enlistment context representing the OCI connection, along with a reference to an MS DTC transaction object. If pTrans is NULL, the OCI connection is de-enlisted from any MS DTC transaction in which it is currently enlisted. You can enlist a previously-enlisted OCI connection in a different MS DTC transaction.
Tests if you are running inside a Microsoft Transaction Server-started transaction.
BOOL OraMTSTransTest();
Returns
Returns true if running inside a Microsoft Transaction Server transaction.
Usage Notes
Microsoft Transaction Server transactional components use OraMTSTransTest() to check if a component is running within the context of a Microsoft Transaction Server transaction. Note that this call can only test Microsoft Transaction Server-started transactions. Transactions started by directly calling the MS DTC are not detected.
Retrieves the OCI error code and message text, if any, from the last OraMTS function operation, typically OraMTSSvcGet() or OraMTSJoinTxn().
BOOL OraMTSOCIErrGet(DWORD* dwErr,
LPCHAR lpcEMsg,
DWORD* lpdLen);
Table 4-9 OraMTSOCIErrGet() Parameters
| Parameter | IN/OUT | Description |
|---|---|---|
|
|
|
Error code |
|
|
|
Buffer for the error message, if any |
|
|
|
Set to the actual number of message bytes |
Returns
Returns true if an OCI error is encountered. Otherwise, false is returned. If true is returned and lpcEMsg and lpdLen are valid, and there is a stashed error message, up to lpdLen bytes are copied into lpcEMsg. lpdLen is set to the actual number of message bytes.
Usage Notes
Example 4-2 illustrates how OraMTSOCIErrGet() retW rieves the OCI error code and OCI error message text, if any, from the last OraMTSSvc() operation on this thread.
Example 4-2 Retrieving the OCI Error Code and Message Text
DWORD dwStat = OraMTSSvcGet("hr",
"invalid_password",
"fin_prod",
"db",
&mysvch,
&myenvh,
ORAMTS_CFLG_ALLDEFAULT);
if (dwStat != ORAMTS_ERR_NOERROR)
{
DWORD dwOCIErr;
char errBuf[MAX_PATH];
DWORD errBufLen = sizeof(effBuf);
if (OraMTSOCIErrGet(&dwOCIErr, &errBuf, &errBufLen))
printf("OCIError %d: %s"\n);
}
This section describes how to use Oracle ODBC Driver with Microsoft Transaction Server and a Oracle Database. No changes to OCI code are necessary for ODBC to operate successfully.
To use Microsoft Transaction Server with either Oracle ODBC Driver 11.1 or Microsoft Oracle ODBC driver, set the connection attribute using the SQLSetConnectAttr function to call the parameter SQL_ATTR_ENLIST_IN_DTC in the ODBC code. This enables you to receive connection pooling and implicit transaction support.
The ODBC Driver Manager distributed with ODBC 3.0 is a Resource Dispenser that supports connection pooling. Oracle ODBC Driver release 11.1 integrates with the ODBC 3.0 Driver Manager by supporting the SQLSetConnectAttr(...,..., SQL_ATTR_ENLIST_IN_DTC) call to enlist or de-enlist the ODBC connection used in MS DTC-coordinated transactions.
Use the Oracle ODBC Driver 11.1 with:
Applications you develop
The sample banking application that Microsoft provides with Microsoft Transaction Server.
To configure Oracle ODBC Driver, follow these steps:
Choose Start > Settings > Control Panel.
The Control Panel window appears.
Double-click ODBC.
The ODBC Data Source Administrator dialog box appears.
Choose the File DSN tab.
To make Oracle ODBC Driver work with Microsoft sample banking application demo, follow these steps. Otherwise, skip this step.
Back up Microsoft mtssamples.dsn file. This file is located in ROOTDRIVE:\program files\common files\odbc\data sources.
Click Yes when prompted.
This deletes the configuration file that enables the Microsoft Transaction Server sample application demo to use the Microsoft ODBC driver.
If you don't intend to use the demo, click Add to create a new File data source name (DSN).
The Create New Data Source wizard appears.
Select Oracle in HOME_NAME.
Click Advanced.
Add the following information in the keywords and values field:
SERVER=database_alias USERNAME=hr PASSWORD=hr_password
where:
SERVER is the The database alias used by the demo to access the database mtsdemo.
USERNAME is the database username for this application, such as hr.
PASSWORD is the database password for username hr.
Verify that the hr schema contains the account and receipt tables.
Click OK.
Click Next to continue with the Create New Data Source wizard.
For the Microsoft sample application, enter mtssamples.dsn (Microsoft ODBC name). This name must exactly match the name you removed in Step 4.
For applications you develop, enter the name of the DSN file that will be used.
Complete the remaining Create New Data Source wizard pages.
Click OK to exit the ODBC Data Source Administrator dialog box.
Exit the Control Panel window.
|
See Also: Microsoft Transaction Server SDK for information |
As an alternative to the Oracle ODBC driver, you can use the Microsoft Oracle ODBC Driver. You should be aware that you would not be able to integrate with OO4O, Oracle Provider for OLE DB, and Oracle Data Provider for .NET if using the Microsoft driver. Also, you will not receive the performance benefits of the Oracle ODBC driver, API support for integration, or Oracle client support services.
After enabling the Microsoft Oracle ODBC Driver, perform these additional steps to configure the Microsoft Oracle ODBC Driver:
To configure the Microsoft Oracle ODBC Driver:
Install Oracle Required Support Files (RSF) and SQL*Net 2.3 or later on the computer where the Microsoft Oracle ODBC Driver is operating.
Run the ORACLE_BASE\ORACLE_HOME\oramts\samples\ sql\omtssamp.sql script.
Use SQL*Net Easy Config to set up a database alias connection. This alias is used in the mtssamples.dsn file.
If you installed the RSFs in a home with Oracle Net installed, be sure to set the following registry parameter at HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE:
ORAOCI = ORA73.DLL
|
See Also: "Setting Up MTS to Access Oracle" in the Microsoft Transaction Server online Help for instructions on enabling the Microsoft Oracle ODBC Driver |
