Use this chart to track the utilization of the Adaptive Server metadata cache for open databases.
The number of active databases, the number of free databases, and the maximum number of databases used are charted.
When Adaptive Server opens a database, it has to access information about it in the respective system table: sysdatabases. The metadata cache for databases lets Adaptive Server access that information that describes it in the sysdatabases row directly in its in-memory structure. This improves performance because it allows the Adaptive Server to bypass expensive calls that require disk access. It also reduces synchronization and spinlock contention when Adaptive Server has to retrieve database information at runtime.
Managing individual metadata caches for databases, indexes, or objects is beneficial for a database that contains a large number of indexes and objects, and where there is high concurrency among users. For more information about configuring the number of metadata caches, see "number of open databases," "number of open indexes," and "number of open objects."