Changing the size of an IBM MQ queue file
You can increase or decrease the maximum size of a queue file.
Before you begin
Before setting a new size for a queue file, use the DISPLAY QLOCAL command to see the
size of the queue file you want to change. For example, issue the following
command:
DISPLAY QLOCAL(SYSTEM.DEFAULT.LOCAL.QUEUE) MAXFSIZE
You receive the following
output:
AMQ8409I: Display queue details
QUEUE(SYSTEM.DEFAULT.LOCAL.QUEUE) TYPE(QLOCAL)
MAXFSIZE(DEFAULT)
which shows that the maximum size of the queue file is the default value of 2,088,960 MB.
About this task
The following procedures show you how to:
- Reduce the maximum size that a queue file can grow to.
- Increase the maximum size that a queue file can grow to.Attention: You should be cautious of increasing the size of queue files without considering the way that your applications are written and the possible effect on performance. Accessing messages at random in a very large queue file can be very slow.
If you are considering increasing the maximum size of a queue file beyond the default you should be cautious of using message selectors such as correlation IDs and IBM® MQ classes for JMS selector strings. Larger queue files are better suited to first-in first-out access to the queue.
Having very large amounts of data in individual queue files should only be done on queue managers that are configured for circular logging, or where media imaging has not been enabled for the individual queue.
You should not limit the size of SYSTEM queues as this could affect the operation of the queue manager.