Administration Getting Started

Tuning the Buffer Pool Size(s)

Buffer pools are defined in "Buffer Pool". Each table space is associated with a buffer pool. When you create a table space, the default buffer pool (called IBMDEFAULTBP) is used. You can modify the size of the default buffer pool. The default of one buffer pool will usually suffice.

For a higher level of database tuning, you can create additional buffer pools and assign table spaces to individual buffer pools. For example, you could create four buffer pools, one each for catalogs (small), temporary space, indexes, and data. The extended buffer pool allows DB2 to take advantage of large amounts of memory. See the Administration Guide for more details.

Altering the Size of the Default Buffer Pool

The Performance Configuration SmartGuide provides a suggested buffer pool size based on your environment. However, if you want to increase the size of the default buffer pool further, follow the steps below.

1. From the Control Center, expand the database for which you want to alter the buffer pool size.

2. Double-click on the Buffer Pool icon. IBMDEFAULTBP is displayed in the contents pane of the Control Center.

3. Click with mouse button 2 on IBMDEFAULTBP, and select Alter from the pop-up menu. The Alter Buffer Pool window opens.

4. Modify the Size in 4 KB pages field, and click on OK.

The change is effective the next time the database is started up (that is, the next time the db2start command is issued).

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