WebSphere Message Brokers
File: ah14450_
Writer: Laura Cowen

Task topic

This build: July 31, 2007 21:30:13

Changing the Database Heap Size on DB2 broker databases

Each database in a DB2 instance is associated with a heap (temporary storage) but the default size of the heap (measured in 4 KB pages) is too low for the broker to use. Therefore, if you create broker databases in DB2, you must increase the value of the Database Heap Size parameter for each broker database to ensure that the heap size is at least 900, which gives the broker database 3600 KB of storage space (that is, 900 multiplied by 4 KB pages).

Changing the Database Heap Size using the DB2 Control Center

To change the Database Heap Size using the DB2 Control Center:
  1. Start the DB2 Control Center.
    • On Windows, click Start > Programs > IBM DB2 > General Administration Tools > Control Center
    • On UNIX and Linux (x86 platform), enter the following command (ensure that you have already run the DB2 profile so that the shell is running the DB2 environment): db2cc
  2. For each broker database that you have created:
    1. In the tree, expand the right-click the database name, then click Configure Parameters. The Database Configuration dialog opens.
    2. In the Database Configuration window, click Performance > DBHEAP.
    3. Click the cell in the Value column, then click the button labelled ... The Change Database Configuration Parameters dialog opens.
    4. Set the value of the DBHEAP parameter to at least 900 (the maximum value that you can enter is 60000), then click OK. The Change Database Configuration Parameters dialog closes and the new value is shown in the cell in the Pending Value column.
    5. Click OK. The new value is applied and a message is displayed to show that it was changed successfully.
    6. Click Close to close the message and return to the main DB2 Control Center window.
The heap size of the broker database is changed.

Changing the Database Heap Size on the command line

  1. Open a DB2 command window.
  2. Enter the following command, where WBRKBKDB is the name of the broker database and 900 is the number of 4 KB pages:
    db2 update database configuration for WBRKBKDB using dbheap 900
The heap size of the broker database is changed.
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This build: July 31, 2007 21:30:13

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