DB2 Administration › DB2 Buffer Pools

DB2 Buffer Pools

Physical I/O requests are a major contributor to DB2 CPU usage. Large buffer pools minimize I/O.

Efficient buffer pools allocation to the DB2 objects ensures the following:

• Fewer I/O operations resulting in faster access to your data
• Reduced I/O contention with data and indexes
• Reduced sorting effort and time for work files for analytical queries

If performance problems exist, discuss with your DB2 administration team to analyze the typical workloads for ReportCenter, and customize the buffer pools to these requirements.

General buffer pool usage guidelines include the following:

• Using BP0 for everything impacts performance. Use BP0 only for the catalog and directory.
• The DB2 subsystem supports up to 80 different buffer pools. Consider using separate buffer pools for the following:
  • Catalog and directory (BP0)
  • DSNDB07
  • Tablespaces
  • Indexes
  • Small, read-only tables
  • Small, frequently updated tables and indexes
  • Large tablespaces supporting random processing

Isolating the ReportCenter application objects in a dedicated buffer pool greatly raises buffer pool hit ratios for the fact tables, improving synchronous I/O and CPU usage.