Guidelines for Setting Up IBM DB2 Buffer Pools

This topic is part of Configuring an IBM DB2 Database for Siebel CRM.

A buffer pool is an area of main system memory that is used for holding pages of data that have been fetched from the tablespace. In IBM DB2, each tablespace is associated with a buffer pool. Adding more space to a buffer pool enhances the performance of the database.

You must have at least three buffer pools for the Siebel tablespaces. You can use the default buffer pool to buffer data pages from all of the Siebel 4-KB tablespaces.

You must also create additional buffer pools with 16-KB and 32-KB page sizes for sorting and other SQL processing. A sample configuration is shown in the following table.

Buffer Pool	Suggested Buffer Pool Size	Page Size
BUF4K	50% of available memory	4 KB
BUF16K	25% of available memory	16 KB
BUF32K	32 MB	32 KB

Different operating systems support different maximum amounts of IBM DB2 addressable memory. Depending on the memory configuration of a given server, the suggested pool sizes for BUF4K and BUF16K buffer pools might exceed these maximums, requiring you to allocate a smaller percentage. To determine the optimal buffer pool sizes, use IBM DB2 monitoring features.

About Buffer Pools and the Full Publish Process

When the Full Publish process runs to generate Siebel Runtime Repository data from the Design Repository (including during the upgrade process for the development database), it makes intensive use of workspace queries, which results in a higher usage of buffer pools. If you encounter errors similar to the following during the Full Publish process, increase the buffer pool sizes above the values shown in the preceding table and try again.

DBCLog DBCLogError 1 000000025c1eca2c:0 2018-12-22 04:50:04 SQLError:
sqlstate 57011: [IBM][CLI Driver][DB2/AIX64] SQL1218N  There are no pages
currently available in bufferpool "4".  SQLSTATE=57011

For more information about the Full Publish process, see Using Siebel Tools and Siebel Database Upgrade Guide.