Dictionary cache

When a session executes an SQL statement that requires access to a system catalog table, the database server reads data from the system catalog tables.

The database server stores the catalog data for each queried table in structures that it can access more efficiently during subsequent queries on that table. These structures are created in the virtual portion of shared memory for use by all sessions. These structures constitute the dictionary cache.

You can configure the size of the dictionary cache with the DD_HASHSIZE and DD_HASHMAX configuration parameters. For more information about these parameters, see the chapter on configuration effects on memory in your HCL OneDB™ Performance Guide.