APP_CTL_HEAP_SZ is not large enough for WMB message processing

Technote (troubleshooting)


You have a problem while processing messages through WebSphere Message Broker (WMB). What you see in the broker logs is that there is a problem with operation to the database. The error message is:

IBM CLI driver db2/nt sql0973n not enough storage available in the "APP_CTL_HEAP" heap to process the statement SQLSTATE=57011.

Resolving the problem

Processing transactions through the message flows can fail if there is not enough storage in the APPL_CTL_HEAP.

The solution to this problem is to increase Application Control heap Size from (default) 128 to something larger; for example 1024 for broker databases.

Note: This value is only a recommendation, and you should try different values to determine which are best suited for your environment.

To increase the parameter:

  1. Start DB2 Instance (if stopped)
  2. Connect to the database
  3. The actual 'db2' command required for increase is:
    db2 => update db config for DBNAME using APPL_CTL_HEAP_SZ 1024
    and then confirm the configuration using the following command:
    db2 => get db config for DBNAME

Historical Number


Product Alias/Synonym

WMB MB WebSphere Message Broker MQ Integrator WBIMB WBI-MB MQSI WMQI

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Document information

More support for:

WebSphere Message Broker

Software version:

6.1, 7.0, 8.0

Operating system(s):

AIX, HP-UX, Linux, OS/390, OS/400, Solaris, Tandem NSK, Windows, z/OS

Reference #:


Modified date:


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