In the course of writing a health check for MQ and IIB this week, I was reminded of some log tuning mystique that we resolved at Hursley concerning queue buffers. As detailed elsewhere, DefaultQBufferSize is the TuningParameters stanza value that determines the size of the non-persistent buffer of a queue. The queue's non-persistent buffer will adopt the size of this parameter based on the value this was set to in the qm.ini when the QM was last started, but before the queue was created. If this value is not set in the qm.ini at that time, then the default value is 128KB. So far, this is pretty much aligned with the 'received wisdom', as long as you looked under the right stone. What is not generally known is that the queue persistent buffer 'equivalent' is not DefaultPQBufferSize (which I will describe shortly), but NewPQBufferSize! NewPQBufferSize: The persistent buffer of a queue will be set to whatever value was when the QM was last started and before the queue
The plan is that this blog will comprise of a series of articles of a how to nature or solutions to technical problems often encountered in the 'field'. What is the field? Well, broadly, Middleware such as MQ, IIB, ... (possibly others) and its interconnectivity and management with other Middleware or tooling.