Modifying IBM MQ queue files
From IBM® MQ 9.2.0, you can control the size of queue files using an attribute on local and model queues. You can display the current size of a queue file, and the maximum size it is currently able to grow to (based on the block size currently in use in that file), using two queue status attributes.
Attribute used to modify queue files
- MAXFSIZE
- Denotes the maximum size of the queue file used by the queue, in megabytes.
- CURFSIZE
- Displays the current size of the queue file in megabytes, rounded up to the nearest megabyte.
- CURMAXFS
- Indicates the current maximum size the queue file can grow to, rounded up to the nearest megabyte, given the current block size in use on a queue.
Block size and granularity
Queue files are divided into segments called blocks. To increase the maximum size of a queue file, the block size or granularity of the queue might need to be changed by the queue manager.
If a newly defined queue is created with a large MAXFSIZE value, the queue is created with a suitable block size. However if an existing queue has its MAXFSIZE value increased, for example by using the ALTER QLOCAL command, it might be necessary to allow the queue to be emptied in order for the queue manager to reconfigure the queue.