Updating statistics

This topic describes when to update statistics and provides an example.

Note: This topic applies only to on-premises environments.

Use the Transact-SQL statement UPDATE STATISTICS if these events occur:

A process suddenly takes much longer than usual to run.
There is a significant change in the key values in an index.
A large amount of data in an indexed column has been added, changed, or removed, or the table has been truncated using the TRUNCATE TABLE statement and then repopulated.

We recommend that you update statistics nightly or weekly.

This example updates the statistics for all indexes on the customer table:

UPDATE STATISTICS customer

To update statistics for all tables in the in the current database, you can run the SQL Server stored procedure sp_updatestats, which uses UPDATE STATISTICS:

EXEC sp_updatestats

For more information, see SQL Server help for UPDATE STATISTICS and sp_updatestats.