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SQL Anywhere 12.0.0 » SQL Anywhere Server - SQL Usage » Monitoring and improving database performance » Improving database performance » Performance improvement tips


Dynamic cache sizing

You can use SQL Anywhere to automatically resize the database cache while the database server is running. However, the effectiveness of dynamic cache sizing is limited by the operating system on which the database server is running and by the amount of available physical memory.

With full dynamic cache sizing, the cache grows when the database server can usefully use more, as long as memory is available, and shrinks when cache memory is required by other applications.

Typically, the cache requirements are assessed by dynamic cache sizing once per minute. However, the assessment frequency may increase to once every five seconds for thirty seconds when a new database is started or when a file grows significantly. After the initial thirty second period, the sampling rate returns to once per minute. File growth of 1/8 since the database started or since the last growth that triggered an increase in the sampling rate is considered significant. This change improves performance further by adapting the cache size more quickly when databases are started dynamically and when a lot of data is inserted.

With dynamic cache sizing you do not need to explicitly configure the database cache.

When an Address Windowing Extensions (AWE) cache is used, dynamic cache sizing is disabled. Only the 32-bit Windows database server can use an AWE cache. See -cw dbeng12/dbsrv12 server option (deprecated).


The use of AWE is deprecated. It is recommended that you use the 64-bit version of the SQL Anywhere database server on a 64-bit Windows operating system if you require a large cache.

 See also