The configuration parameters that control the total number of databases, indexes, partitions and objects that can be open simultaneously are managed by the metadata caches. The metadata caches reside in the server structures portion of Adaptive Server memory. Use these parameters to configure space for these caches:
number of open databases
number of open indexes
number of open objects
number of open partitions
See Chapter 5, Setting Configuration Parameters,” in the System Administration Guide, Volume 1.
When Adaptive Server opens a database or accesses an index, partition, or object, it reads information about it in the corresponding system tables: the information for databases is in sysdatabases, the information for indexes is in sysindexes, the information for partitions is in syspartitions, and so on.
The metadata caches for databases, indexes, partitions, or objects allow Adaptive Server to access the information that describe them in sysdatabases, sysindexes, syspartitions, or sysobjects directly in its in-memory structure. In doing so, Adaptive Server bypasses expensive calls that require disk access, thus improving performance. It also reduces synchronization and spinlock contention when Adaptive Server needs to retrieve database, index, partition, or object information at runtime.Managing individual metadata caches is beneficial for a database that contains a large number of indexes, partitions, and objects, and where there is high concurrency among users.
