DB2 Version 9.7 for Linux, UNIX, and Windows

SYSTS_CLEAR_EVENTS procedure - Delete indexing events from an index's event table

This procedure deletes indexing events from an index's event table used for administration.

The name of the event table can be found in the view SYSIBMTS.TSINDEXES in column EVENTVIEWNAME. Every index update operation that processes at least one document produces informational and, in some cases, error entries in the event table. For automatic updates, the event table has to be regularly inspected. Document specific errors must be corrected by changing the document content. After correcting the errors, the events can be cleared (and should be, in order not to consume too much space).

The procedure issues a CLEAR EVENTS FOR INDEX text search administration command on the database server.

Syntax


>>-SYSTS_CLEAR_EVENTS--(--index_schema--,--index_name--,-------->

>--message_locale--,--message--)-------------------------------><

The schema is SYSPROC.

Procedure parameters

index_schema: An input argument of type VARCHAR(128) that specifies the schema of the text search index. The index_schema must follow the naming restriction for DB2® schema names. If the argument is null or an empty string, the value of CURRENT SCHEMA is used. The index_schema is case-sensitive.
index_name: An input argument of type VARCHAR(128) that specifies the name of the index. Together with index_schema, it uniquely identifies a text search index in a database. The index_name is case-sensitive.
message_locale: An input argument of type VARCHAR(33) that specifies the locale to be used for any error message returned. If the argument is null or an empty string, or the message files for the specified locale are not available on the server, 'en_US' is used.
message: An output argument of type VARCHAR(32K) that specifies a warning or informational message for a successfully completed operation.

Authorization

The privileges held by the authorization ID of the statement must include at least one of the following authorities:

CONTROL privilege on the table on which the index is defined
DBADM authority

Examples

Example 1: In the following example, SYSTS_CLEAR_EVENTS is being called for a text search index that was created with index_schema 'db2ts' and index_name 'myTextIndex'. Any error messages are requested to be returned in English. When the procedure succeeds, the output parameter message indicative of the successful operation is returned to the caller.

  CALL SYSPROC.SYSTS_CLEAR_EVENTS('db2ts', 'myTextIndex', 'en_US', ?)

The following example is a sample output from this query.

  Value of output parameters
  --------------------------
  Parameter Name  : MESSAGE
  Parameter Value : Operation completed successfully.

  Return Status = 0

Example 2: In the following example, SYSTS_CLEAR_EVENTS is called to clear the event table entries for a text search index with index_schema 'db2ts' and index_name 'myTextIndex'. This index does not exist and results in an error.

  CALL SYSPROC.SYSTS_CLEAR_EVENTS('db2ts', 'myTextIndex', 'en_US', ?)

The following example is a sample output from this query.

  SQL20427N An error occurred during a text search administration 
  procedure or command. The error message is "CIE00316 Text search 
  index "db2ts"."myTextIndex" does not exist. ". SQLSTATE 38H14

Usage notes

Text search administration procedures use an existing connection to the database. The current transaction might be committed or rolled back depending on the completion of the procedures. It is therefore recommended to commit all transaction changes before executing a text search administration procedure to avoid any unexpected impact from a commit or rollback in the procedure. One way to achieve this is to turn on AUTOCOMMIT.
Note: You may run into a deadlock if a transaction is not committed before executing a text search administration operation, as the same database objects may be affected and the operation waits for the previous step to commit. This may occur, for example, if AUTOCOMMIT is turned off and a table is created followed by creating a text index without an explicit commit between the two transactions.
Multiple procedures or commands cannot be run concurrently on a text search index if they might conflict. Some of the conflicting procedures and commands are:
- SYSTS_ALTER procedure or ALTER INDEX db2ts command
- SYSTS_DISABLE procedure or DISABLE DATABASE FOR TEXT db2ts command
- SYSTS_DROP procedure or DROP INDEX db2ts command
- STOP FOR TEXT db2ts command
- SYSTS_UPDATE procedure or UPDATE INDEX db2ts command
If there is a conflict, the procedure returns an SQLCODE -20426 and SQLSTATE 38H13.
When regular updates are scheduled (see UPDATE FREQUENCY options in SYSTS_CREATE or SYSTS_ALTER procedures), the event table should be checked regularly.
To clean up the DB2 Text Search event table for a text search index, use the SYSTS_CLEAR_EVENTS procedure or CLEAR EVENTS FOR INDEX db2ts command after you have checked the reason for the event and removed the source of the error.
Ensure that changes have been made to all rows referenced in the event table. By changing the rows in the user table, you ensure that when you run the SYSTS_UPDATE procedure or UPDATE INDEX db2ts command again, an attempt is made to index the erroneous documents again.
When this command is issued, the event table is cleared.