MaxUncommittedMsgs (MQLONG)
This is the maximum number of uncommitted messages
that can exist within a unit of work. The number of uncommitted messages is
the sum of the following since the start of the current unit of work:
- Messages put by the application with the MQPMO_SYNCPOINT option
- Messages retrieved by the application with the MQGMO_SYNCPOINT option
- Trigger messages and COA report messages generated by the queue manager
for messages put with the MQPMO_SYNCPOINT option
- COD report messages generated by the queue manager for messages retrieved
with the MQGMO_SYNCPOINT option
The following are not counted as uncommitted
messages:
- Messages put or retrieved by the application outside a unit of work
- Trigger messages or COA/COD report messages generated by the queue manager
as a result of messages put or retrieved outside a unit of work
- Expiration report messages generated by the queue manager (even if the
call causing the expiration report message specified MQGMO_SYNCPOINT)
- Event messages generated by the queue manager (even if the call causing
the event message specified MQPMO_SYNCPOINT or MQGMO_SYNCPOINT)
Notes:
- Exception report messages are generated by the Message Channel Agent (MCA),
or by the application, and are treated in the same way as ordinary messages
put or retrieved by the application.
- When a message or segment is put with the MQPMO_SYNCPOINT option, the
number of uncommitted messages is incremented by one regardless of how many
physical messages actually result from the put. (More than one physical message
might result if the queue manager needs to subdivide the message or segment.)
- When a distribution list is put with the MQPMO_SYNCPOINT option, the number
of uncommitted messages is incremented by one for each
physical message that is generated. This can be as small as one, or as
great as the number of destinations in the distribution list.
The lower limit for this attribute is 1; the upper limit is 999 999 999.
To determine the value of this attribute, use the MQIA_MAX_UNCOMMITTED_MSGS
selector with the MQINQ call.