Adjusting buffer pool storage that is used for sort work files

Sort processing uses pages in the Db2 buffer pool for its initial input, for work files that contain intermediate results, and for the final output.

About this task

The buffer pools are not always dedicated to sort work files. The amount of sort activity determines how much the buffer pools are used. For heavy sort activity, sort records that have been written to the work files are temporarily written to the disk until buffer pool space becomes available.

Db2 considers the buffers that it uses for work files as sequentially accessed pages.

Procedure

To adjust the percentage of the buffer pool that is used for work files:

Use the VPSEQT parameter of the ALTER BUFFERPOOL command. If a buffer pool is used only for sort work files, you might set VPSEQT to 99%. If the buffer pool is used for sparse indexes or declared global temporary tables, set VPSEQT to 90%. If you do not have enough allocated storage to complete sort processing, you must allocate more disk space for the work file database.