Buffer pool thresholds

How Db2 uses of a buffer pool is governed by several preset values called thresholds.

Each buffer pool threshold is a level of use which, when exceeded, causes Db2 to take some action. Certain thresholds might indicate a buffer pool shortage problem, while other thresholds merely report normal buffer management by Db2. The level of use is usually expressed as a percentage of the total size of the buffer pool. For example, the immediate write threshold of a buffer pool is set at 97.5%. When the percentage of unavailable pages in a buffer pool exceeds that value, Db2 writes pages to disk when updates are completed.

For very small buffer pools, of fewer than 1000 buffers, some of the thresholds might be lower to prevent buffer pool full conditions, but those thresholds are not described.