A system administrator can use optdiag to change column-level statistics.
WARNING! Using optdiag to alter statistics can improve the performance of some queries. However, optdiag overwrites existing information in the system tables, which can affect all queries for a given table.
Use extreme caution and test all changes thoroughly on all queries that use the table. If possible, test the changes using optdiag simulate on a development server before loading the statistics into a production server.
If you load statistics without simulate mode, be prepared to restore the statistics, if necessary, either by using an untouched copy of optdiag output or by re-running update statistics.
Do not attempt to change any statistics by running an update, delete, or insert command.
You can use optdiag output from a 32-bit Adaptive Server to change statistics in another 32-bit Adaptive Server, but not a 64-bit Adaptive Server. Similarly, do not use optdiag output from a 64-bit Adaptive Server as input to a 32-bit Adaptive Server.
After you change statistics using optdiag, running create index or update statistics overwrites the changes. The commands succeed, but print a warning message:
WARNING: Edited statistics are overwritten. Table: ’titles’ (objectid 208003772), column: ’type’.
