The database cache is an area of memory used by the database server to store database pages for repeated fast access. The more pages that are accessible in the cache, the fewer times the database server needs to read data from disk. As reading data from disk is a slow operation, the amount of cache available is often a key factor in determining performance.

For systems that are not dedicated database servers, restricting the cache size may improve overall system performance by leaving more memory available for other processes. In general, dynamic cache sizing tunes the cache size appropriately and automatically by monitoring the system as a whole.

You can specify the -c options to control the size of the database cache on the database server command line when the database is started.

The database server messages window displays the size of the cache at startup, and you can use the following statement to obtain the current size of the cache:

SELECT PROPERTY( 'CurrentCacheSize' );

Encrypted databases must have sufficient cache to minimize I/O operations because these operations are more expensive on encrypted databases than on unencrypted databases since encryption and/or decryption must be performed for each operation.

 See also