Publications under syncpoint

In IBM MQ publish/subscribe, syncpoint can be used by publishers or internally by the queue manager.

Publishers use syncpoint when they issue MQPUT/MQPUT1 calls with the MQPMO_SYNCPOINT option. All messages delivered to subscribers count towards the maximum number of uncommitted messages in a unit of work.The MAXUMSGS queue manager attribute specifies this limit. If the limit is reached then the publisher receives the 2024 (07E8) (RC2024): MQRC_SYNCPOINT_LIMIT_REACHED reason code.

When a publisher issues MQPUT/MQPUT1 calls using MQPMO_NO_SYNCPOINT with the MQPMO_RETAIN option, or topic delivery options NPMSGDLV/PMSGDLV with values ALL or ALLDUR, the queue manager uses internal syncpoints to guarantee that messages are delivered as requested. The publisher can receive the 2024 (07E8) (RC2024): MQRC_SYNCPOINT_LIMIT_REACHED reason code if the limit is reached within the scope of the publisher MQPUT/MQPUT1 call.