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Guidelines for Setting Up DB2 UDB Bufferpools

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

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

You must have at least three bufferpools for the Siebel table spaces. You can use the default bufferpool (called IBMDEFAULTBP) to buffer data pages from all the Siebel 4-KB table spaces.

You must also create additional bufferpools with 16-KB and 32-KB page sizes for sorting and other SQL processing. A sample configuration is shown in Table 10.

Table 10. Sample Bufferpool Configuration
Suggested Bufferpool Size
Page Size


50% of available memory

4 KB


25% of available memory

16 KB


32 MB

32 KB

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

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