New-function APARs for Db2 12 in 2025

Tip: Depending on how when and how you order the product code for Db2 12 or Db2 13, you might find that the external changes from any of the following APARs are already built-in when you install a new Db2 environment or migrate to Db2 13. Also, you can expect that external changes from the following APARs with availability dates earlier than 2022-06 are likely to be already built-in when you migrate to Db2 13, regardless of whether you apply the PTFs in Db2 12.
Support for a queue parameter in the CAF OPEN function

APAR PH65922 (May 2025) enhances the OPEN function for the call attachment facility (CAF) with a new optional queue parameter that specifies whether a thread is rejected instead of being queued based on the threshold of the CTHREAD subsystem parameter being reached.

The CTHREAD subsystem parameter specifies the maximum number of concurrent allied threads allowed by Db2 for z/OS®. Any create thread request made after this threshold has been exceeded is queued for later processing once resources become available.

The queue parameter is an 8-byte area that contains the string 'NOQUEUE'. When 'NOQUEUE' is specified, a create thread request that would otherwise be queued based on the CTHREAD value is instead rejected with return code 8, and reason code 00F3005A is returned to the calling application.

For more information, see the following related topics:

Datagram message support in MQListener

APAR PH63420 (February 2025) enhances the MQListener support in Db2 12 or later to send reply messages for datagram messages.

For more information, see the following related topics: