optdiag can generate statistics that can be used to simulate a user environment without requiring a copy of the table data. This permits analysis of query optimization using a very small database. For example, simulated statistics can be used:
For Technical Support replication of optimizer problems
To perform “what if” analysis to plan configuration changes
In most cases, you will use simulated statistics to provide information to Technical Support or to perform diagnostics on a development server.
See “Requirements for loading and using simulated statistics” for information on setting up a separate database for using simulated statistics.
You can also load simulated statistics into the database from which they were copied. Simulated statistics are loaded into the system tables with IDs that distinguish them from the actual table data. The set statistics simulate on command instructs the server to optimize queries using the simulated statistics, rather than the actual statistics.
