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Safety of messages

 

In addition to the usual recovery features of WebSphere MQ, distributed queue management ensures that messages are delivered properly by using a syncpoint procedure coordinated between the two ends of the message channel. If this procedure detects an error, it closes the channel to allow you to investigate the problem, and keeps the messages safely in the transmission queue until the channel is restarted.

The syncpoint procedure has an added benefit in that it attempts to recover an in-doubt situation when the channel starts up. (In-doubt is the status of a unit of recovery for which a syncpoint has been requested but the outcome of the request is not yet known.) Also associated with this facility are the two functions:

  1. Resolve with commit or backout

  2. Reset the sequence number

The use of these functions occurs only in exceptional circumstances because the channel recovers automatically in most cases.

 

Parent topic:

Making your applications communicate


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