Defining buffer pools

Use the Cache Properties Buffer Pool tab to view the properties of the current buffer pool. A Buffer Pool is a common pool which can be shared among caches. You can add and remove buffer pools, and you can change their size.

When you first create a cache, all space is assigned to the default memory (buffer) pool consisting of buffers that are the default I/O size for Adaptive Server (2K on most platforms). After creating a cache, you can create additional pools with buffers larger than the default. I/Os for these pools are the size of their buffers—for example, 4K I/Os for a pool with 4K buffers. In a database with a high level of I/O activity, defining pools with buffers larger than the default can make I/Os more efficient.

Moving space between buffer pools within a cache takes effect immediately. You do not need to restart Adaptive Server.

Each buffer pool you create is identified by the size of its buffers. The following sizes are allowed: 2K (the default on most Adaptive Servers), 4K, 8K, and 16K.

In any cache, you can have only one pool of each buffer size.

When you create a buffer pool, you reassign space from the default pool. For example, if you create a data cache with 50MB of space, all of the space is initially assigned to the default pool. If you create a 30MB pool of 16K buffers, the default pool is reduced to 20MB. If you remove a 4K, 8K, or 16K buffer pool, the space returns to the default pool.