CODEWITHSUNDEEP
ibm-mq
John Edelmann
John Edelmann

Reputation: 181

WMQ Message Logging Scenarios v 7.5

In the following scenario, i'm curious as to what happens as it relates to what's in the active LOG files of the queue manager in question. Linear Logging is being used.

What activity (if any) is experienced by the MQ Active LOGS, during a scenario where a queue with say, 100 messages, is being READ with a JMS context attribute (looking for a specific message) -- that, for the case of this arguement, it will NEVER find. All messages are read off the queue, but none are committed. The messages therefore were never actually deleted from the queue; does the queue manager, however, record such GET operations so as to recover these "in flight" conditions, should the queue manager Crash while this is happening? We recently experienced a situation where the dequeue rate from a specific queue was in the 4000-4500 msg / min range, while the queue depth was only about 2500. We surmise that more than 1 such process thread were trying to read off a JMS message by context (sort of like with correlation ID I suppose), but without any hope of ever actually finding a message it was looking for (due to a probable misconfiguration). During this time, the active LOGS filled up rapidly. Is it likely that such wanton dequeue rates as we saw were the culprit?

Upvotes: 0

Views: 239

Answers (1)

Umamahesh P
Umamahesh P

Reputation: 1244

MQ writes log records for persistent messages during get and put. More details can be found here:

http://pic.dhe.ibm.com/infocenter/wmqv7/v7r5/topic/com.ibm.mq.dev.doc/q023070_.htm

Upvotes: 1

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