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SQL Anywhere 11.0.1 (Français) » SQL Anywhere Server - Database Administration » Configuring Your Database » Database options » Introduction to database options » Alphabetical list of options


subsume_row_locks option [database]

Controls when the database server acquires individual row locks for a table.

Allowed values

On, Off




If the subsume_row_locks option is On (the default) then whenever a table t is locked exclusively with LOCK TABLE t IN EXCLUSIVE MODE, the database server no longer acquires individual row locks for t.

This can result in a significant performance improvement if extensive updates are made to t in a single transaction, especially if t is large relative to cache size. It also allows for atomic update operations that are larger than the lock table can currently handle (approximately 2-4 million rows).

When this option is On, keyset cursors over a table locked in this fashion will return row changed warnings for every row in the cursor, if any row in the database has been modified. Note that the database server could turn an updatable cursor with an ORDER BY into a keyset cursor as a result.