Bug 472312

Summary:	Prefetch information
Product:	Red Hat Enterprise MRG	Reporter:	William Henry <whenry>
Component:	Messaging_Programming_Reference	Assignee:	Jonathan Robie <jonathan.robie>
Status:	CLOSED ERRATA	QA Contact:	Jeff Needle <jneedle>
Severity:	high	Docs Contact:
Priority:	high
Version:	1.1	CC:	gsim
Target Milestone:	1.3	Keywords:	Documentation
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Hardware:	All
OS:	Linux
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Description William Henry 2008-11-19 23:36:23 UTC

Description of problem:

There doesn't seem to be a lot of descriptions anywhere on how to use prefetch.

pre-acquire is default .. i.e. it assumes that the consumer is going to take ownership of message and once acknowledged it can be removed from the queue. 

no-acquire allows you to fetch messages without acquiring them. This is useful for both subscribing to messages with taking responsibility for processing (stock feed) or for browsing messages on a queue. 

I found this very useful:
https://wiki.108.redhat.com/wiki/index.php/AMQP:154,162:Proposal

Also Jonathan had some slides on no-acquire and pre-acquire in the training material. 


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Comment 2 Jonathan Robie 2009-11-30 14:55:37 UTC

In the User's Guide, the Sessions chapter has a section called "Message acquisition and acceptance", which covers this.

The C++ API documentation for Session has a series of examples for "Accepting, Acquiring, Rejecting, or Releasing Messages". The Python API documentation is sparse in general, and does not include this. For both languages, the new high level APIs need to be documented in general. 

Java uses the Java JMS API.