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SQL Anywhere 11.0.1 » SQL Anywhere Server - SQL Reference » Using SQL » SQL statements » SQL statements (P-Z)

 

REFRESH TEXT INDEX statement

Refreshes a text index.

Syntax
REFRESH TEXT INDEX text-index-name ON [ owner.]table-name
[ WITH { 
      ISOLATION LEVEL isolation-level 
      | EXCLUSIVE MODE 
      | SHARE MODE } ]
[ FORCE { BUILD | INCREMENTAL } ]
Parameters
  • WITH clause   Use the WITH clause to specify what kind of locks to obtain on the underlying base tables during the refresh. The types of locks obtained determine how the text index is populated and how concurrency for transactions is affected. If you do not specify the WITH clause, the default is WITH ISOLATION LEVEL READ UNCOMMITTED, regardless of any isolation level set for the connection.

    You can specify the following WITH clause options:

    • ISOLATION LEVEL isolation-level   Use WITH ISOLATION LEVEL to change the isolation level for the execution of the refresh operation. For information about isolation levels, see Using transactions and isolation levels, and Isolation levels and consistency.

      The original isolation level of the connection is restored at the end of the statement execution.

    • EXCLUSIVE MODE   Use WITH EXCLUSIVE MODE if you do not want to change the isolation level, but want to guarantee that the data is updated to be consistent with committed data in the underlying table. When using WITH EXCLUSIVE MODE, exclusive table locks are placed on the underlying base table and no other transaction can execute queries, updates, or any other action against the underlying table(s) until the refresh operation is complete. If table locks cannot be obtained, the refresh operation fails and an error is returned. See Table locks.

    • SHARE MODE   Use WITH SHARE MODE to give read access on the underlying table to other transactions while the refresh operation takes place. When this clause is specified, shared table locks are obtained on the underlying base table before the refresh operation is performed and and are held until the refresh operation completes. See Table locks.

  • FORCE clause   Use this clause to specify the refresh method. If this clause is not specified, the database server decides whether to do an incremental update or a full rebuild based on how much of the table has changed. See Text index refresh types.

    • FORCE BUILD clause   Use this clause to force a complete rebuild of the text index.

    • FORCE INCREMENTAL clause   Use this clause to force an incremental update of the text index.

Remarks

This statement can only be used on text indexes defined as MANUAL REFRESH or AUTO REFRESH.

When using the FORCE clause, you can examine the results of the sa_text_index_stats system procedure to decide whether a complete rebuild (FORCE BUILD), or incremental update (FORCE INCREMENTAL) is most appropriate. See sa_text_index_stats system procedure.

You cannot execute the REFRESH TEXT INDEX statement on a text index that is defined as IMMEDIATE REFRESH.

For MANUAL REFRESH text indexes, use the sa_text_index_stats system procedure to determine whether the text index should be refreshed. Divide pending_length by doc_length, and use the percentage as a guide for deciding whether a refresh is required. To determine the type of rebuild required, use the same process for deleted_length and doc_count.

Permissions

Must be the owner of the underlying table, or have either DBA authority or REFERENCES permission.

This statement cannot be executed when there are cursors opened with the WITH HOLD clause that use either statement or transaction snapshots. See Snapshot isolation.

Side effects

Automatic commit.

See also
Standards and compatibility
  • SQL/2003   Vendor extension.

Example

The following statement refreshes a text index called MarketingTextIndex, forcing it to be rebuilt.

REFRESH TEXT INDEX MarketingTextIndex ON MarketingInformation
   FORCE BUILD;