Recovering the message queues

In a non-shared-queues environment, you can recover the message queues during an IMS restart if the previous shutdown included the DUMPQ or the SNAPQ keyword.

Specify the BUILDQ keyword on the /NRESTART or /ERESTART command to restore the messages to the message queue data sets from the IMS log. Specify the FORMAT keyword on the /NRE or /ERE command if you also want to reinitialize the message queue data sets.

In order to use the /NRE BUILDQ command, the system must be shut down using a /CHECKPOINT DUMPQ | PURGE command. To use the /ERE BUILDQ command, you need only a prior /CHECKPOINT SNAPQ command.

Restriction: If a /NRE BUILDQ or /ERE BUILDQ command fails and you cold start IMS or cold start DC, messages are lost and are not processed.

You can use the IBM® IMS Queue Control Facility for z/OS® to select messages from the OLDS (or SLDS) and reinsert them into the IMS message queues after an IMS cold start.

For a shared-queues environment, CQS automatically rebuilds the message queues if the coupling facility fails. You can also use the SETXCF START,REBUILD command to rebuild the queues manually.