Configuring the Database Cache

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The database cache consists of all database pages (also called buffers) held in memory at one time. Database cache size is the number of database pages. You can set the default size of the database cache at three levels:

• Server level: applies to all databases
• Database level: applies only to a single database (using gfix or ALTER DATABASE SET PAGE CACHE to set the size for a specific database)

• Connection level: applies only to a specific isql connection

We recommend setting cache size at the database level rather than at the server level. This reduces the likelihood of inappropriate database cache sizes.

Every database on a server requires RAM equal to the cache size (number of database pages) times the page size. By default, the cache size is 2048 pages per database and the page size is 4KB. Thus, a single database running at the default setting requires 8MB of memory, but three such databases require 24MB of memory.

Topics

• Default Cache Size Per Database
• Default Cache Size Per isql Connection
• Setting Cache Size in Applications
• Default Cache Size Per Server
• Verifying Cache Size