A System Administrator can use optdiag to change column-level statistics.
WARNING! Using optdiag to alter statistics can improve the performance of some queries. Remember, however, that 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 rerunning update statistics.
Do not attempt to change any statistics by running an update, delete, or insert command.
optdiag output from a 32-bit Adaptive Server can be used to change statistics in another 32-bit Adaptive Server, but not a 64-bit Adaptive Server. Similarly, optdiag output from a 64-bit Adaptive Server should not be used 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. This message indicates that altered statistics for the titles.type column have been overwritten:
WARNING: Edited statistics are overwritten. Table: ’titles’ (objectid 208003772), column: ’type’.
