Cache size   The amount of cache memory available to the database server can be a key factor in affecting performance. The more memory made available to the database server, the faster it performs. The cache holds information that may be required more than once. Accessing information in cache is faster than accessing it from disk. The default initial cache size is computed based on the amount of physical memory, the operating system, and the size of the database files. The database server automatically adjusts the cache size as necessary. See Dynamic cache sizing.

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' );

For more information about performance tuning, see Performance monitoring and diagnostic tools.

The following table summarizes the database server options available for controlling the cache.

Multiprogramming level   The database server's multiprogramming level specifies the maximum number of database server tasks that can execute concurrently. In general, a higher multiprogramming level increases the overall throughput of the database server by permitting more requests to execute simultaneously. However, if the requests compete for the same resources, increasing the multiprogramming level can lead to additional contention and lengthen transaction response time.

By default, SQL Anywhere automatically adjusts the database server's multiprogramming level. In some cases you can lower the throughput of the system by increasing the multiprogramming level. The following options allow you to control the database server's multiprogramming level manually:

For more information about the multiprogramming level in SQL Anywhere, see Database server configuration of the multiprogramming level.

Number of processors   If you are running on a multi-processor computer using a network database server, you can set the number of processors with the -gt option. See -gt database server option and SQL Anywhere threading.

The number of CPUs that the database server can use may also be affected by your license or SQL Anywhere edition. See Editions and licensing.

Other performance-related options   There are several options available for tuning network performance, including -gb (database process priority), and -u (buffered disk I/O). See SQL Anywhere database server syntax.