9 XLA Reference

XLA function reference

This section provides reference information for XLA core functions and XLA data type conversion functions. The functions are listed in alphabetical order.

ttXlaAcknowledge

Description

This function is used to acknowledge that one or more records have been read from the transaction log by the ttXlaNextUpdate or ttXlaNextUpdateWait function.

After you make this call, the bookmark is reset so that you cannot reread any of the previously returned records. Call ttXlaAcknowledge only when messages have been completely processed.

Note that ttXlaAcknowledge is an expensive operation that should be used only as necessary. Calling ttXlaAcknowledge more than once per reading of the transaction log file does not reduce the volume of the transaction log since XLA only purges transaction logs a file at a time. To detect when a new transaction log file is generated, you can find out which log file a bookmark is in by examining the purgeLSN (represented by the PURGELSNHIGH and PURGELSNLOW values) for the bookmark in the system table SYS.TRANSACTION_LOG_API. You can then call ttXlaAcknowledge to purge the old transaction log files. (Note that you must have ADMIN or SELECT ANY TABLE privilege to view this table.)

The second purpose of ttXlaAcknowledge is to ensure that the XLA application does not see the acknowledged records if it were to connect to a previously used bookmark by calling the ttXlaPersistOpen function with the XLAREUSE option. If you intend to reuse a bookmark, call ttXlaAcknowledge to reset the bookmark position to the current record before calling ttXlaClose.

See "Retrieving update records from the transaction log" for a discussion about using this function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaAcknowledge(ttXlaHandle_h handle)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

rc = ttXlaAcknowledge(xlahandle);

See also

ttXlaClose

Description

Closes an XLA handle that was opened by ttXlaPersistOpen. See "Terminating an XLA application" for a discussion about using this function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaClose(ttXlaHandle_h handle)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

To close the XLA handle opened in the previous example, use the following call:

rc = ttXlaClose(xlahandle);

See also

ttXlaConvertCharType

Description

Converts the column data indicated by the colinfo and tup parameters into the connection character set associated with the transaction log handle and places the result in a buffer.

Required privilege

XLA

Syntax

SQLRETURN ttXlaConvertCharType (ttXlaHandle_h handle,
                                ttXlaColDesc_t*  colinfo,
                                void* tup,
                                void* buf,
                                size_t buflen)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

ttXlaDateToODBCCType

Description

Converts a TTXLA_DATE_TT value to an ODBC C value usable by applications. See "Converting complex data types" for a discussion about using this function.

Call this function only on a column of data type TTXLA_DATE_TT. The data type can be obtained from the ttXlaColDesc_t structure returned by the ttXlaGetColumnInfo function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaDateToODBCCType(void* fromData,
                               out DATE_STRUCT* returnData)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

ttXlaDecimalToCString

Description

Converts a TTXLA_DECIMAL_TT value to a string usable by applications. The scale and precision values can be obtained from the ttXlaColDesc_t structure returned by the ttXlaGetColumnInfo function. The scale parameter specifies the maximum number of digits after the decimal point. If the decimal value is larger than 1, the precision parameter should specify the maximum number of digits before and after the decimal point. If the decimal value is less than 1, precision equals scale.

Call this function only for a column of type TTXLA_DECIMAL_TT. The data type can be obtained from the ttXlaColDesc_t structure returned by the ttXlaGetColumnInfo function.

See "Converting complex data types" for a discussion about using this function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaDecimalToCString(void* fromData,
                                out char* returnData,
                                SQLSMALLINT precision,
                                SQLSMALLINT scale)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

This example assumes you have obtained the offset, precision, and scale values from a ttXlaColDesc_t structure and used the offset to obtain a decimal value, pColVal, in a row returned in a transaction log record.

char decimalData[50];
static ttXlaColDesc_t colDesc[255];

rc = ttXlaDecimalToCString(pColVal, (char*)&decimalData,
                                     colDesc->precision, 
                                     colDesc->scale);

ttXlaDeleteBookmark

Description

Deletes the bookmark associated with the specified transaction log handle. After the bookmark has been deleted, it is no longer accessible and its identifier may be reused for another bookmark. The deleted bookmark is no longer associated with the database handle and the effect is the same as having opened the connection with the XLANONE option.

If the bookmark is in use, it cannot be deleted until it is no longer in use.

See "Deleting bookmarks" for a discussion about using this function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaDeleteBookmark(ttXlaHandle_h handle)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

Delete the bookmark for xlahandle:

rc = ttXlaDeleteBookmark(xlahandle);

See also

ttXlaError

Description

Reports details of any errors encountered from the previous call on the given transaction log handle. Multiple errors may be returned through subsequent calls to ttXlaError. The error stack is cleared following each call to a function other than ttXlaError itself and ttXlaErrorRestart.

See "Handling XLA errors" for a discussion about using this function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaError(ttXlaHandle_h handle,
                     out SQLINTEGER* errCode,
                     out char* errMessage,
                     SQLINTEGER maxLen,
                     out SQLINTEGER* retLen)

Parameters

Returns

Returns SQL_SUCCESS if error information is returned, or SQL_NO_DATA_FOUND if no more errors are found in the error stack. If the errMessage buffer is not large enough, ttXlaError returns SQL_SUCCESS_WITH_INFO.

Example

There can be multiple errors on the error stack. This example shows how to read them all.

char message[100];
SQLINTEGER code;

for (;;) {
  rc = ttXlaError(xlahandle, &code, message, sizeof (message), &retLen);
  if (rc == SQL_NO_DATA_FOUND)
      break;
  if (rc == SQL_ERROR) {
      printf("Error in fetching error message\n");
      break;
  }
  else {
      printf("Error code %d: %s\n", code, message);
  }
}

Note

If you use multiple threads to access a TimesTen transaction log over a single XLA connection, TimesTen creates a latch to control concurrent access. If for some reason the latch cannot be acquired by a thread, the XLA function returns SQL_INVALID_HANDLE.

See also

ttXlaErrorRestart

ttXlaErrorRestart

Description

Resets the error stack so that an application can reread the errors. See "Handling XLA errors" for a discussion about using this function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaErrorRestart(ttXlaHandle_h handle)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

rc = ttXlaErrorRestart(xlahandle);

See also

ttXlaError

ttXlaGetColumnInfo

Description

Retrieves information about all the columns in the table. Normally, the output parameter for number of columns returned, nreturned, is set to the number of columns returned in colinfo. The systemTableID or userTableID parameter describes the desired table. This call is serialized with respect to changes in the table definition.

See "Obtaining column descriptions" for a discussion about using this function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaGetColumnInfo(ttXlaHandle_h handle,
                             SQLUBIGINT systemTableID,
                             SQLUBIGINT userTableID,
                             out ttXlaColDesc_t* colinfo,
                             SQLINTEGER maxcols,
                             out SQLINTEGER* nreturned)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

For this example, assume the following definitions:

ttXlaColDesc_t colinfo[20];
SQLUBIGINT systemTableID, userTableID;
SQLINTEGER ncols;

To get the description of up to 20 columns using the system table identifier, issue the following call:

rc = ttXlaGetColumnInfo(xlahandle, systemTableID, 0, colinfo, 20, &ncols);

Likewise, the user table identifier can be used:

rc = ttXlaGetColumnInfo(xlahandle, 0, userTableID, colinfo, 20, &ncols);

See "ttXlaColDesc_t" for details and an example on how to access the column data in a returned row.

See also

ttXlaGetLSN

Description

Returns the Current Read log record identifier for the connection specified by the transaction log handle. See "How bookmarks work" for a discussion about using this function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaGetLSN(ttXlaHandle_h handle,
                      out tt_XlaLsn_t* LSN)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

This example returns the Current Read log record identifier, CurLSN.

tt_XlaLsn_t CurLSN;

rc = ttXlaGetLSN(xlahandle, &CurLSN);

See also

ttXlaSetLSN

ttXlaGetTableInfo

Description

Retrieves information about the rows in the table (refer to the description of the ttXlaTblDesc_t data type.) If the userTableID parameter is nonzero, then it is used to locate the desired table. Otherwise, the systemTableID value is used to locate the table. If both are zero, an error is returned. The description is stored in the output parameter tblinfo. This call is serialized with respect to changes in the table definition.

Required privilege

XLA

Syntax

SQLRETURN ttXlaGetTableInfo(ttXlaHandle_h handle,
                            SQLUBIGINT systemTableID,
                            SQLUBIGINT userTableID,
                            out ttXlaTblDesc_t* tblinfo)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

For this example, assume the following definitions:

ttXlaTblDesc_t tabinfo; 
SQLUBIGINT systemTableID, userTableID;

To get table information using a system identifier, find the system table identifier using ttXlaTableByName or other means and issue the following call:

rc = ttXlaGetTableInfo(xlahandle, systemTableID, 0, &tabinfo);

Alternatively, the table information can be retrieved using a user table identifier:

rc = ttXlaGetTableInfo(xlahandle, 0, userTableID, &tabinfo);

See also

ttXlaGetColumnInfo

ttXlaGetVersion

Description

This function is used in combination with ttXlaSetVersion to ensure XLA applications written for older versions of XLA operate on a new version. The configured version is typically the older version, while the actual version is the newer one.

The function retrieves the currently configured XLA version and stores it into configuredVersion parameter. The actual version of the underlying XLA is stored in actualVersion. Due to calls on ttXlaSetVersion, the results in configuredVersion may vary from one call to the next, but the results in actualVersion remain the same.

See "XLA basics" for a discussion about using this function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaGetVersion(ttXlaHandle_h handle,
                          out ttXlaVersion_t* configuredVersion,
                          out ttXlaVersion_t* actualVersion)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

Assume the following directions for this example:

ttXlaVersion_t configured, actual;

To determine the current version configuration, use the following call:

rc = ttXlaGetVersion(xlahandle, &configured, &actual);

See also

ttXlaNextUpdate

Description

This function fetches up to a specified maximum number of update records from the transaction log and returns the records associated with committed transactions to a specified buffer. The actual number of returned records is reported in the nreturned output parameter. This function requires a bookmark to be present in the database and to be associated with the connection used by the function.

Each call to ttXlaNextUpdate resets the bookmark to the last record read to enable the next call to ttXlaNextUpdate to return the next list of records.

See "Retrieving update records from the transaction log" for a discussion about using this function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaNextUpdate(ttXlaHandle_h handle,
                          out ttXlaUpdateDesc_t*** records,
                          SQLINTEGER maxrecords,
                          out SQLINTEGER* nreturned)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

This example retrieves up to 100 records and describes a loop in which each record can be processed:

ttXlaUpdateDesc_t** records;
SQLINTEGER nreturned;
SQLINTEGER i;

rc = ttXlaNextUpdate(xlahandle, &records, 100, &nreturned);
/* Check for errors; if none, process the records */
for (i = 0; i < nreturned; i++) {
  process(records[i]);
}

Notes

Updates are generated for all data definition statements, regardless of tracking status. Updates are generated for data update operations for all tracked tables associated with the bookmark.

In addition, updates are generated for certain special operations, including assigning application-level identifiers for tables and columns and changing a table's tracking status.

See also

ttXlaNextUpdateWait

Description

This is similar to the ttXlaNextUpdate function, with the addition of a seconds parameter that specifies the number of seconds to wait if no records are available in the transaction log. The actual number of seconds of wait time can be up to two seconds more than the specified seconds value.

Also see "Retrieving update records from the transaction log".

Required privilege

XLA

Syntax

SQLRETURN ttXlaNextUpdateWait(ttXlaHandle_h handle,
                              out ttXlaUpdateDesc_t*** records,
                              SQLINTEGER maxrecords,
                              out SQLINTEGER* nreturned,
                              SQLINTEGER seconds)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

This example retrieves up to 100 records and will wait for up to 60 seconds if there are no records available in the transaction log.

ttXlaUpdateDesc_t** records;
SQLINTEGER nreturned;
SQLINTEGER i;

rc = ttXlaNextUpdateWait(xlahandle, &records, 100, &nreturned, 60);
/* Check for errors; if none, process the records */
for (i = 0; i < nreturned; i++) {
  process(records[i]);
}

See also

ttXlaNumberToBigInt

Description

Converts a TTXLA_NUMBER value to a SQLBIGINT value usable by an application.

Call this function only for a column of type TTXLA_NUMBER. The data type can be obtained from the ttXlaColDesc_t structure returned by the ttXlaGetColumnInfo function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaNumberToBigInt(void* fromData,
                              SQLBIGINT* bint)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

ttXlaNumberToCString

Description

Converts a TTXLA_NUMBER value to a character string usable by an application.

Call this function only for a column of type TTXLA_NUMBER. The data type can be obtained from the ttXlaColDesc_t structure returned by the ttXlaGetColumnInfo function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaNumberToCString(ttXlaHandle_h handle,
                               void* fromData,
                               char* buf,
                               int buflen
                               int* reslen)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

ttXlaNumberToDouble

Description

Converts a TTXLA_NUMBER value to a long floating point number value usable by applications.

Call this function only for a column of type TTXLA_NUMBER. The data type can be obtained from the ttXlaColDesc_t structure returned by the ttXlaGetColumnInfo function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaNumberToDouble(void* fromData,
                              double* dbl)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

ttXlaNumberToInt

Description

Converts a TTXLA_NUMBER value to a SQLINTEGER value usable by an application.

Call this function only for a column of type TTXLA_NUMBER. The data type can be obtained from the ttXlaColDesc_t structure returned by the ttXlaGetColumnInfo function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaNumberToInt(void* fromData,
                           SQLINTEGER* ival)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

ttXlaNumberToSmallInt

Description

Converts a TTXLA_NUMBER value to a SQLSMALLINT value usable by an application.

Call this function only for a column of type TTXLA_NUMBER. The data type can be obtained from the ttXlaColDesc_t structure returned by the ttXlaGetColumnInfo function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaNumberToSmallInt(void* fromData,
                                SQLSMALLINT* smint)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

ttXlaNumberToTinyInt

Description

Converts a TTXLA_NUMBER value to a tiny integer value usable by an application.

Call this function only for a column of type TTXLA_NUMBER. The data type can be obtained from the ttXlaColDesc_t structure returned by the ttXlaGetColumnInfo function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaNumberToTinyInt(void* fromData,
                               SQLCHAR* tiny)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

ttXlaNumberToUInt

Description

Converts a TTXLA_NUMBER value to an unsigned integer value usable by an application.

Call this function only for a column of type TTXLA_NUMBER. The data type can be obtained from the ttXlaColDesc_t structure returned by the ttXlaGetColumnInfo function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaNumberToInt(void* fromData,
                           SQLUINTEGER* ival)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

ttXlaOraDateToODBCTimeStamp

Description

Converts a TTXLA_DATE value to an ODBC timestamp.

Call this function only for a column of type TTXLA_DATE. The data type can be obtained from the ttXlaColDesc_t structure returned by the ttXlaGetColumnInfo function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaOraDateToODBCTimeStamp(void* fromData,
                                      TIMESTAMP_STRUCT* returnData)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

ttXlaOraTimeStampToODBCTimeStamp

Description

Converts a TTXLA_TIMESTAMP value to an ODBC timestamp.

Call this function only for a column of type TTXLA_TIMESTAMP. The data type can be obtained from the ttXlaColDesc_t structure returned by the ttXlaGetColumnInfo function.

Syntax

SQLRETURN ttXlaOraTimeStampToODBCTimeStamp(void* fromData,
                                           TIMESTAMP_STRUCT* returnData)

Required privilege

XLA

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

ttXlaPersistOpen

Description

Initializes a transaction log handle to a database to enable access to the transaction log. The hdbc parameter is an ODBC connection handle to a database. Create only one XLA handle for each ODBC connection. After you have created an XLA handle on an ODBC connection, do not issue any other ODBC calls over the ODBC connection until it is closed by ttXlaClose.

The tag is a string that identifies the XLA bookmark (see "About XLA bookmarks"). The tag can identify a new bookmark, either non-replicated or replicated, or one that exists in the system, as specified by the options parameter. The handle parameter is initialized by this call and must be provided on each subsequent call to XLA.

Some actions can be done without a bookmark. When performing these types of actions, you can use the XLANONE option to access the transaction log without a bookmark. Actions that cannot be done without a bookmark are the following:

• ttXlaAcknowledge

• ttXlaGetLSN

• ttXlaSetLSN

• ttXlaNextUpdate

• ttXlaNextUpdateWait

Multiple applications can concurrently read from the transaction log. See "Initializing XLA and obtaining an XLA handle" for a discussion about using this function.

When this function is successful, XLA sets the autocommit mode to off.

If this function fails but still creates a handle, the handle must be closed to prevent memory leaks.

Required privilege

XLA

Syntax

SQLRETURN ttXlaPersistOpen(SQLHDBC hdbc,
                           SQLCHAR* tag,
                           SQLUINTEGER options,
                           out ttXlaHandle_h* handle)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

This example opens a transaction log, returns a handle named xlahandle, and creates a new non-replicated bookmark named mybookmark:

SQLHDBC hdbc;
ttXlaHandle_h xlahandle;

rc = ttXlaPersistOpen(hdbc, ( SQLCHAR*)mybookmark,
                      XLACREAT, &xlahandle);

Alternatively, create a new replicated bookmark as follows:

SQLHDBC hdbc;
ttXlaHandle_h xlahandle;

rc = ttXlaPersistOpen(hdbc, ( SQLCHAR*)mybookmark,
                      XLAREPL, &xlahandle);

Note

Multithreaded applications should create a separate XLA handle for each thread. If multiple threads must use the same XLA handle, use a mutex to serialize thread access to that XLA handle so that only one thread can execute an XLA operation at a time.

See also

ttXlaRowidToCString

Description

Converts a ROWID value to a string value usable by applications.

Required privilege

XLA

Syntax

SQLRETURN ttXlaRowidToCString(void* fromData, char* buf, int buflen)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

char charbuf[18];
void* rowiddata;
/* ... */
rc = ttXlaRowidToCString(rowiddata, charbuf, sizeof(charbuf));

ttXlaSetLSN

Description

Sets the Current Read log record identifier for the database specified by the transaction handle. The specified LSN value should be returned from ttXlaGetLSN. It cannot be a user-created value and cannot be earlier than the current bookmark Initial Read log record identifier.

See "About XLA bookmarks" for a discussion about using this function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaSetLSN(ttXlaHandle_h handle,
                      tt_XlaLsn_t* LSN)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

This example sets the Current Read log record identifier to CurLSN.

tt_XlaLsn_t CurLSN;

rc = ttXlaSetLSN(xlahandle, &CurLSN);

See also

ttXlaGetLSN

ttXlaSetVersion

Description

Sets the version of XLA to be used by the application. This version must be either the same as the version received from ttXlaGetVersion or from an earlier version.

See "XLA basics" for a discussion about using this function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaSetVersion(ttXlaHandle_h handle,
                          ttXlaVersion_t* version)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

To set the configured version to the value specified in requestedVersion, issue the following call:

rc = ttXlaSetVersion(xlahandle, &requestedVersion);

See also

ttXlaTableByName

Description

Finds the system and user table identifiers for a table or materialized view by providing the owner and name of the table or view. See "Specifying which tables to monitor for updates" for a discussion about using this function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaTableByName(ttXlaHandle_h handle,
                           char* owner,
                           char* name,
                           out SQLUBIGINT* sysTableID,
                           out SQLUBIGINT* userTableID)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

To get the system and user table IDs associated with the table PURCHASING.INVOICES, use the following call:

SQLUBIGINT sysTableID;
SQLUBIGINT userTableID;

rc = ttXlaTableByName(xlahandle, "PURCHASING", "INVOICES", 
                      &sysTableID, &userTableID);

See also

ttXlaTableStatus

ttXlaTableStatus

Description

Returns the update status for a table. Identify the table by specifying either a user ID (userTableID) or a system ID (systemTableID). If userTableID is nonzero, it is used to locate the table. Otherwise systemTableID is used. If both are zero, an error is returned.

Specifying a value for newstatus sets the update status to *newstatus. A nonzero status means the table specified by systemTableID is available through XLA. Zero means the table is not tracked. Changes to table update status are effective immediately.

Updates to a table are tracked only if update tracking was enabled for the table at the time the update was performed. This call is serialized with respect to updates to the underlying table. Therefore, transactions that update the table run either completely before or completely after the change to table status.

To use ttXlaTableStatus, the user must be connected to a bookmark. The function reports inserts, updates, and deletes only to the bookmark that has subscribed to the table. It reports DDL events to all bookmarks. DDL events include CREATAB, DROPTAB, CREAIND, DROPIND, CREATVIEW, DROPVIEW, CREATSEQ, DROPSEQ, CREATSYN, DROPSYN, ADDCOLS, DRPCOLS, TRUNCATE, SETTBL1, and SETCOL1 transactions. See "ttXlaUpdateDesc_t" for information about these event types.

See "Specifying which tables to monitor for updates" for a discussion about using this function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaTableStatus(ttXlaHandle_h handle,
                           SQLUBIGINT systemTableID,
                           SQLUBIGINT userTableID,
                           out SQLINTEGER* oldstatus,
                           SQLINTEGER* newstatus)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

The following examples assume that the system or user table identifiers are found using ttXlaTableByName or some other means.

Assume these declarations for the example:

SQLUBIGINT systemTableID;
SQLUBIGINT userTableID;
SQLINTEGER currentStatus, requestedStatus;

To find the status of a table given its system table identifier, use the following call:

/* Get system table identifier into systemTableID, then ... */
rc = ttXlaTableStatus(xlahandle, systemTableID, 0,
                      &currentStatus, NULL);

The currentStatus value will be nonzero if update tracking for the table is enabled, or zero otherwise.

To enable update tracking for a table given a system table identifier, set the requested status to 1 as follows:

requestedStatus = 1;

rc = ttXlaTableStatus(xlahandle, systemTableID, 0,
                      NULL, &requestedStatus);

You can set a new update tracking status and retrieve the current status in a single call, as in the following example:

requestedStatus = 1;

rc = ttXlaTableStatus(xlahandle, systemTableID, 0,
                      &currentStatus, &requestedStatus);

The above call enables update tracking for a table by system table identifier and retrieves the prior update tracking status in the variable currentStatus.

All of these examples can be done using user table identifiers as well. To retrieve the update tracking status of a table through its user table identifier, use the following call:

/* Get system table identifier into userTableID, then ... */

rc = ttXlaTableStatus(xlahandle, 0, userTableID,
                      &currentStatus, NULL);

See also

ttXlaTableByName

ttXlaTableVersionVerify

Description

Verifies that the cached table definitions are compatible with the XLA record being processed. Table definitions change only when the ALTER TABLE statement is used to add or remove columns.

You can monitor the XLA stream for XLA records of transaction type ADDCOLS and DRPCOLS to avoid the overhead of using this function. When an XLA record of transaction type ADDCOLS or DROPCOLS is encountered, refresh the table and column definitions. See "Inspecting record headers and locating row addresses" for information about monitoring XLA records for transaction type.

Required privilege

XLA

Syntax

SQLRETURN ttXlaTableVersionVerify(ttXlaHandle_h handle
                                  ttXlaTblVerDesc_t* table,
                                  ttXlaUpdateDesc_t* record
                                  out SQLINTEGER* compat)

Parameters

Returns

Returns SQL_SUCCESS if cached table definition is compatible with the XLA record being processed. Otherwise, use ttXlaError to report the error.

Example

This example checks the compatibility of a table.

SQLINTEGER compat;
ttXlaTbVerDesc_t table;
ttXlaUpdateDesc_t* record;
/*
 * Get the desired table definitions into the variable "table"
 */
rc = ttXlaTableVersionVerify(xlahandle, &table, record, &compat);
if (compat) {
/*
 * Compatible
 */
}
else {
/*
 * Not compatible or some other error occurred
 * If not compatible, issue a call to ttXlaVersionTableInfo and
 * ttXlaVersionColumnInfo to get the new definition.
 */
}

See also

ttXlaTimeToODBCCType

Description

Converts a TTXLA_TIME value to an ODBC C value usable by applications. See "Converting complex data types" for a discussion about using this function.

Call this function only for a column of type TTXLA_TIME. The data type can be obtained from the ttXlaColDesc_t structure returned by the ttXlaGetColumnInfo function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaTimeToODBCCType (void* fromData,
                                out TIME_STRUCT* returnData)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

This example assumes you have used the offset value returned in a ttXlaColDesc_t structure to obtain a time value, pColVal, from a row returned in a transaction log record.

TIME_STRUCT time;

rc = ttXlaTimeToODBCCType(pColVal, &time);

ttXlaTimeStampToODBCCType

Description

Converts a TTXLA_TIMSTAMP_TT value to an ODBC C value usable by applications. See "Converting complex data types" for a discussion about using this function.

Call this function only for a column of type TTXLA_TIMSTAMP_TT. The data type can be obtained from the ttXlaColDesc_t structure returned by the ttXlaGetColumnInfo function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaTimeStampToODBCCType(void* fromData,
                                    out TIMESTAMP_STRUCT* returnData)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

This example assumes you have used the offset value returned in a ttXlaColDesc_t structure to obtain a timestamp value, pColVal, from a row returned in a transaction log record.

TIMESTAMP_STRUCT timestamp;

rc = ttXlaTimeStampToODBCCType(pColVal, &timestamp);

ttXlaVersionColumnInfo

Description

Retrieves information about the columns in a table for which a change update XLA record must be processed.

Required privilege

XLA

Syntax

SQLRETURN ttXlaVersionColumnInfo(ttXlaHandle_h handle,
                                 ttXlaUpdateDesc_t* record,
                                 out ttXlaColDesc_t* colinfo,
                                 SQLINTEGER maxcols,
                                 out SQLINTEGER* nreturned)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

For this example, assume the following definitions:

ttXlaHandle_h xlahandle
ttXlaUpdateDesc_t* record;
ttXlaColDesc_t colinfo[20];
SQLINTEGER ncols;

The following call retrieves the description of up to 20 columns:

rc = ttXlaVersionColumnInfo(xlahandle, record, colinfo, 20, &ncols);

ttXlaVersionCompare

Description

Compares two XLA versions and returns the result.

Required privilege

XLA

Syntax

SQLRETURN ttXlaVersionCompare(ttXlaHandle_h handle,
                              ttXlaVersion_t* version1,
                              ttXlaVersion_t* version2,
                              out SQLINTEGER* comparison)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

To compare the configured version against the actual version of XLA, issue the following call:

ttXlaVersion_t configured, actual;
SQLINTEGER comparision;

rc = ttXlaGetVersion (xlahandle, &configured, &actual);
rc = ttXlaVersionCompare (xlahandle, &configured, &actual,
                          &comparison);

Notes

When connecting two systems with XLA-based replication, use the following protocol:

1. At the primary site, retrieve the XLA version using ttXlaGetVersion. Send this version information to the standby site.

2. At the standby site, retrieve the XLA version using ttXlaGetVersion. Use ttXlaVersionCompare to determine which version is earlier. The earlier version number must be used to ensure proper operation between the two sites. Use ttXlaSetVersion to specify the version of the interface to use at the standby site. Send the earlier version number back to the primary site.

3. When the chosen version is received at the primary site, use ttXlaSetVersion to specify the version of XLA to use.

See also

ttXlaVersionTableInfo

Description

Retrieves the table definition for the change update record that must be processed. The table description is stored in the tableinfo output parameter.

Required privilege

XLA

Syntax

SQLRETURN ttXlaVersionTableInfo(ttXlaHandle_h handle,
                                ttXlaUpdateDesc_t* record,
                                out ttXlaTblVerDesc_t* tblinfo)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

For this example, assume the following definitions:

ttXlaHandle_h xlahandle;
ttXlaUpdateDesc_t* record;
ttXlaTblVerDesc_t tabinfo;

The following call retrieves a table definition:

rc = ttXlaVersionTableInfo(xlahandle, record, &tabinfo);

XLA replication function reference

TimesTen replication as described in Oracle TimesTen In-Memory Database Replication Guide is sufficient for most customer needs; however, it is also possible to use XLA functions to replicate updates from one database to another. Implementing your own replication scheme on top of XLA in this way is fairly complicated, but can be considered if TimesTen replication is not feasible for some reason.

This section documents the functions that are exclusive to using XLA as a replication mechanism. Functions are listed in alphabetical order.

ttXlaApply

This function is part of XLA replication functionality and is not appropriate for use in a typical XLA application.

Description

Applies an update to the database associated with the transaction log handle. The return value indicates whether the update was successful. The return also shows if the update encountered a persistent problem. (To see whether the update encountered a transient problem such as a deadlock or timeout, you must call ttXlaError and check the error code.)

If the ttXlaUpdateDesc_t record is a transaction commit, the underlying database transaction is committed. No other transaction commits are performed by ttXlaApply. If the parameter test is true, the "old values" in the update description are compared against the current contents of the database for record updates and deletions. If the old value in the update description does not match the corresponding row in the database, this function rejects the update and returns an sb_ErrXlaTupleMismatch error.

See "Using XLA as a replication mechanism" for a discussion about using this function.

Required privilege

ADMIN

Additional privileges may be required on the target database for the ttXlaApply operation. For example, to apply a CREATETAB (create table) record to the target database, you must have CREATE TABLE or CREATE ANY TABLE privilege, as appropriate.

Syntax

SQLRETURN ttXlaApply(ttXlaHandle_h handle,
                     ttXlaUpdateDesc_t* record,
                     SQLINTEGER test)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

If test is 1 and ttXlaApply detects an update conflict, an sb_ErrXlaTupleMismatch error is returned.

Example

This example applies an update to a database without testing for the previous value of the existing record:

ttXlaUpdateDesc_t record;
rc = ttXlaApply(xlahandle, &record, 0);

Note

When calling ttXlaApply, it is possible for the update to timeout or deadlock with concurrent transactions. In such cases, it is the application's responsibility to roll the transaction back and reapply the updates.

See also

ttXlaCommit

This function is part of XLA replication functionality and is not appropriate for use in a typical XLA application.

Description

Commits the current transaction being applied on the transaction log handle. This routine commits the transaction regardless of whether the transaction has completed. You can call this routine to respond to transient errors (timeout or deadlock) reported by ttXlaApply, which applies the current transaction if it does not encounter an error.

See "Handling timeout and deadlock errors" for a discussion about using this function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaCommit(ttXlaHandle_h handle)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

rc = ttXlaCommit(xlahandle);

See also

ttXlaGenerateSQL

This function is part of XLA replication functionality and is not appropriate for use in a typical XLA application.

Description

Generates a SQL DML or DDL statement that expresses the effect of the update record. The generated statement is not applied to any database. Instead, the statement is returned in the given buffer, whose maximum size is specified by the maxLen parameter. The actual size of the buffer is returned in actualLen. For update and delete records, ttXlaGenerateSQL requires a primary key or a unique index on a non-nullable column to generate the correct SQL.

The generated SQL statement is encoded in the connection character set that is associated with the ODBC connection of the XLA handle.

Also see "Replicating updates to a non-TimesTen database".

Required privilege

XLA

Syntax

SQLRETURN ttXlaGenerateSQL(ttXlaHandle_h handle,
                           ttXlaUpdateDesc_t* record,
                           out char* buffer,
                           SQLINTEGER maxLen,
                           out SQLINTEGER* actualLen)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

This example generates the text of a SQL statement that is equivalent to the UPDATE expressed by an update record:

ttXlaUpdateDesc_t record;
char buffer[200];
/*
 * Get the desired update record into the varable record.
 */

SQLINTEGER actualLength;

rc = ttXlaGenerateSQL(xlahandle, &record, buffer, 200,
                      &actualLength);

Note

The ttXlaGenerateSQL function cannot generate SQL statements for update records associated with a table that has been dropped or altered since the record was generated.

See also

ttXlaLookup

This function is part of XLA replication functionality and is not appropriate for use in a typical XLA application.

Description

This function looks for a record in the given table with key values according to the keys parameter. The formats of the keys and result records are the same as for ordinary rows. This function requires a primary key on the underlying table.

Required privilege

XLA

Syntax

SQLRETURN ttXlaLookup(ttXlaHandle_h handle,
                      ttXlaTableDesc_t* table,
                      void* keys,
                      out void* result,
                      SQLINTEGER maxsize,
                      out SQLINTEGER* retsize)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

This example looks up a record given a pair of integer key values. Before this call, table should describe the desired table and keybuffer contains a record with the key columns set.

char keybuffer[100];
char recbuffer[2000];
ttXlaTableDesc_t table;
SQLINTEGER recordSize;

rc = ttXlaLookup(xlahandle, &table, keybuffer, recbuffer,
                 sizeof (recbuffer), &recordSize);

See also

ttXlaRollback

This function is part of XLA replication functionality and is not appropriate for use in a typical XLA application.

Description

Rolls back the current transaction being applied on the transaction log handle. You can call this routine to respond to transient errors (timeout or deadlock) reported by ttXlaApply.

See "Handling timeout and deadlock errors" for a discussion about using this function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaRollback(ttXlaHandle_h handle)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

rc = ttXlaRollback(xlahandle);

See Also

ttXlaTableCheck

This function is part of XLA replication functionality and is not appropriate for use in a typical XLA application.

Description

When using XLA as a replication mechanism, this function verifies that the named table in the ttXlaTblDesc_t structure received from a master database is compatible with a subscriber database or database associated with the transaction log handle. The compat parameter indicates whether the tables are compatible.

See "Checking table compatibility between databases" for a discussion about using this function.

Required privilege

XLA

Syntax

SQLRETURN ttXlaTableCheck(ttXlaHandle_h handle,
                          ttXlaTblDesc_t* table,
                          ttXlaColDesc_t* columns,
                          out SQLINTEGER* compat)

Parameters

Returns

Returns SQL_SUCCESS if call is successful. Otherwise, use ttXlaError to report the error.

Example

This example checks the compatibility of a table:

SQLINTEGER compat;
ttXlaTblDesc_t table;
ttXlaColDesc_t columns[20];
/*
 * Get the desired table and column definitions into
 * the variables "table" and "columns"
 */
rc = ttXlaTableCheck(xlahandle, &table, columns, &compat);
if (compat) {
    /* Compatible */
}
else {
    /*
     * Not compatible or some other error occurred
     */
}

See also

C data structures used by XLA

This section describes the C data structures used by the XLA functions described in this chapter. These structures are defined in the following file:

install_dir/include/tt_xla.h

You must include this file when building your XLA application.

ttXlaNodeHdr_t

Most C data structures begin with a standard header that describes the data record type and length. The standard header has the type ttXlaNodeHdr_t.

This header has the following fields.

ttXlaUpdateDesc_t

This structure describes an update operation to a single row (or tuple) in the database. Each update record returned by a ttXlaNextUpdate or ttXlaNextUpdateWait function begins with a fixed length ttXlaUpdateDesc_t header followed by zero to two rows from the database. The row data differs depending on the record type reported in the ttXlaUpdateDesc_t header:

• No rows are present in a COMMITONLY record.

• One row is present in INSERTTUP or DELETETUP.

• Two rows are present in an UPDATETUP record to report the row data before and after the update, respectively.

• Special format rows are present in CREATAB, DROPTAB, CREAIND, DROPIND, CREATVIEW, DROPVIEW, CREATSEQ, DROPSEQ, CREATSYN, DROPSYN, ADDCOLS, and DRPCOLS records, which are described in "Special update data formats".

The flags field is a bit-map of special options for the record update.

The connID field identifies the ODBC connection handle that initiated the update. This value can be used to determine if updates came from the same connection.

A separate commit XLA record is generated when a call to the ttApplicationContext procedure is not followed by an operation that generates an XLA record. See "Passing application context" for a description of the ttApplicationContext procedure.

Note

XLA cannot receive notification of the following:

• CREATE VIEW or DROP VIEW for a non-materialized view

• CREATE GLOBAL TEMPORARY TABLE or DROP TABLE for a temporary table

The only XLA records that can be generated from an ALTER TABLE operation are of the following types:

• ADDCOLS or DRPCOLS when columns are added or dropped

• CREAIND or DROPIND when a unique attribute of a column is modified

While sequence creates (CREATESEQ) and drops (DROPSEQ) are visible through XLA, sequence increments are not.

All deletes resulting from cascading deletes and aging are visible through XLA. The flags value (discussed in the following table) indicates when deletes are due to cascading or aging.

The fields of the update header defined by ttXlaUpdateDesc_t are as follows.

TT_UPDCOMMIT     1
TT_UPDFIRST      2
TT_UPDREPL       4
TT_UPDCOLS       8
TT_UPDDEFAULT   64
TT_CASCDEL     256
TT_AGING       512

Special update data formats

The data contained in an update record follows the ttXlaTblDesc_t header. This section describes the data formats for the special update records related to specific SQL operations.

CREATE TABLE

For a CREATE TABLE operation, the special row value consists of the ttXlaTblDesc_t record describing the new table, followed by the ttXlaColDesc_t records that describe each column.

ALTER TABLE

For an ALTER TABLE operation, the special row value consists of a ttXlaDropTableTup_t or ttXlaAddColumnTup_t value, followed by a ttXlaColDesc_t record that describes the column.

ttXlaDropTableTup_t

For a DROP TABLE operation, the row value is as follows.

ttXlaTruncateTableTup_t

For a TRUNCATE TABLE operation, the row value is as follows.

ttXlaCreateIndexTup_t

For a CREATE INDEX operation, the row value is as follows.

ttXlaDropIndexTup_t

For a DROP INDEX operation, the row value is as follows.

ttXlaAddColumnTup_t

For an ADD COLUMN operation, the row value is as follows.

Following this special row are the ttXlaColDesc_t records describing the new columns.

ttXlaDropColumnTup_t

For a DROP COLUMN operation, the row value is as follows.

Following this special row is an array of ttXlaColDesc_t records describing the columns that were dropped.

ttXlaCreateSeqTup_t

For a CREATE SEQUENCE operation, the row value is as follows.

ttXlaDropSeqTup_t

For a DROP SEQUENCE operation, the row value is as follows.

ttXlaViewDesc_t

For a CREATE VIEW operation, the row value is as follows.

ttXlaDropViewTup_t

For a DROP VIEW operation, the row value is as follows.

ttXlaCreateSynTup_t

For a CREATE SYNONYM operation, the row value is as follows.

ttXlaDropSynTup_t

For a DROP SYNONYM operation, the row value is as follows.

ttXlaSetTableTup_t

The description of the SET TABLE ID operation uses the previously assigned application table identifier in the main part of the update record and provides the new value of the application table identifier in the following special row.

ttXlaSetColumnTup_t

The description of the SET COLUMN ID operation provides the following special row:

ttXlaSetStatusTup_t

A change in a table's replication status provides the following special row:

Locating the row data following a ttXlaUpdateDesc_t header

See "Retrieving update records from the transaction log" and "Inspecting record headers and locating row addresses" for a detailed discussion on obtaining update records and inspecting the contents of ttXlaUpdateDesc_t headers. Below is a summary of these procedures.

The update header is immediately followed by the row data. The row data is stored in an internal format with the offsets given in the ttXlaColDesc_t structure returned by ttXlaGetColumnInfo.

You can locate the address of the row data by adding the address of the update header to its size.

For example:

char* Row = (char*)&ttXlaUpdateDesc_t +
             sizeof(ttXlaUpdateDesc_t);

For UPDATETUP records, there are two rows of data following the ttXlaUpdateDesc_t header. The first row contains the data before the update, and the second row the data after the update.

Since the new row is right after the old row, you can calculate its address by adding the address of the old row to its length (tuple1).

For example:

char* oldRow = (char*)&ttXlaUpdateDesc_t +
                sizeof(ttXlaUpdateDesc_t);
char* newRow = oldRow + ttXlaUpdateDesc_t.tuple1;

See "ttXlaColDesc_t" for details on how to access the column data in a returned row.

ttXlaVersion_t

To permit future extensions to XLA, a version structure ttXlaVersion_t describes the current XLA version and structure byte order. This structure is returned by the ttXlaGetVersion function.

This structure has the following fields:

ttXlaTblDesc_t

Table information is portrayed through the ttXlaTblDesc_t structure. This structure is returned by the ttXlaGetTableInfo function.

This structure has the following fields:

The inline row size includes space for all fixed-width columns, null column flags, and pointer information for variable-length columns. Each varying-length column occupies four bytes of inline row space.

Note the following if the table has a declared primary key:

• The nPrimCols value is greater than 0.

• The primColsSys array contains the column numbers of the primary key, in the same order in which they were originally declared with the CREATE TABLE statement.

• The primColsUser array contains the corresponding application-specified column identifiers.

ttXlaTblVerDesc_t

This data structure contains the table version number and ttXlaTblDesc_t. It is returned by ttXlaVersionTableInfo. This structure has the following fields:

ttXlaColDesc_t

Column information is given through this structure, which is returned by the ttXlaGetColumnInfo function.

The structure has the following fields:

The procedures for obtaining a ttXlaColDesc_t structure and inspecting its contents are described in "Inspecting column data". Below is a summary of these procedures.

The ttXlaColDesc_t structure is returned by the ttXlaGetColumnInfo function. This structure contains the metadata needed to access column information in a particular table. For example, you can use the offset field to locate specific column data in the row or rows returned in an update record after the ttXlaColDesc_t structure. By adding the offset to the address of a returned row, you can locate the address to the column value. You can then cast this value to the corresponding C types according to the dataType field, or pass it to one of the conversion routines described in "Converting complex data types".

TimesTen row data consists of fixed-length data followed by any variable-length data.

• For fixed length column data, ttXlaColDesc_t returns the offset and size of the column data. The offset is relative to the beginning of the fixed part of the record. See Example 9-1 below.

• For variable-length column data (VARCHAR2, NVARCHAR2, and VARBINARY), offset is an address that points to a four-byte offset value. By adding the offset address to the offset value, you can obtain the address of the column data in the variable-length portion of the row. The first n bytes at this location is the length of the data, followed by the actual data (where n is 4 on 32-bit platforms or 8 on 64-bit platforms). For variable-length data, the returned size value is the maximum allowable column size. See Example 9-1 below.

For columns that can have null values, nullOffset points to a null byte in the record. This value is 1 if the column is null, or 0 if it is not null. See "Detecting null values" for a discussion.

The flags bits define whether the column is nullable, part of a primary key, or stored out of line.

The sysColNum value is the system column number to assign to the column. This value begins with 1 for the first column.

ttXlaColDesc_t colDesc;

void* pColVal = colDesc->offset + row;

*((SQLINTEGER*) pColVal))

tt_ptrint* var_len = (tt_ptrint*)((char*)pColVal +
                    *((int*)pColVal));
char* var_data = (char*)(var_len+1);
char* buffer = malloc(*var_len+1);
memcpy(buffer,var_data,*var_len);
buffer[*var_len] = (char)NULL; /* NULL terminate the string */
printf("%s\n",buffer);
free(buffer);

tt_LSN_t

Description of log record identifier used by bookmarks. This structure is used by the ttXlaUpdateDesc_t structure.

tt_XlaLsn_t

Description of a log record identifier used by bookmarks. This structure is returned by the ttXlaGetLSN function and used by the ttXlaSetLSN function.

The checksum is specific to an XLA handle to ensure that every log record identifier is related to a known XLA connection.