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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

 

update_statistics option [database]

Controls the gathering of statistics during query execution.

Allowed values

On, Off

Default

On

Remarks

The database server collects statistics during normal query execution and uses the gathered statistics to self-tune the column statistics. You can set the update_statistics option Off to disable the gathering of statistics during query execution.

Under normal circumstances, it should not be necessary to turn this option off.

The update_statistics option does not affect changes to statistics as a result of updates to data (LOAD/INSERT/UPDATE/DELETE). To control whether statistics are updated based on these statements, use the collect_statistics_on_dml_updates database option.

The difference between the collect_statistics_on_dml_updates option and the update_statistics option is that the update_statistics option compares the actual number of rows that satisfy a predicate with the number of rows that are estimated to satisfy the predicate, and then updates the estimates. The collect_statistics_on_dml_updates option modifies the column statistics based on the values of the specific rows that are inserted, updated, or deleted.

See also