Message store or storage adapter specification

The queue uses a queue store adapter to handle its communications with the storage device. Adapters are interfaces between WebSphere MQ Everyplace and hardware devices, such as disks or networks, or software, such as databases. Adapters are pluggable components, allowing the queue store to be easily changed.

All types of queue other than those that are remote and synchronous require a message store to store their messages. Each queue can specify what type of store to use, and where it is located. The queue characteristic Queue_FileDesc is used to specify the type of message store and to provide parameters for it. The file descriptor takes the form:

For example assuming MsgLog is defined as a WebSphere MQ Everyplace alias:

MsgLog:d:\QueueManager\ServerQM12\Queues

A number of storage adapters are provided and include:

The choice of adapter determines the persistence and resilience of messages. For example, if a memory adapter is used, the messages are only as resilient as the memory. Memory may be a much faster medium than disk, but is highly volatile in comparison.

If a message store is not defined when creating a queue, the default is to use the message store specified on creation of the queue manager.

Note:
Under the C codebase, there is only one supplied message store, and one adapter, therefore the format of the queue store is fixed the MsgLog is left as a placeholder for future expansion.

Examples of where to use this option are:

Take the following into consideration when setting the Queue_FileDesc field:



© IBM Corporation 2002. All Rights Reserved