Bug 703984

Summary: The Persistence section should reference producer flow control.
Product: Red Hat Enterprise MRG Reporter: Ken Giusti <kgiusti>
Component: Messaging_Installation_and_Configuration_GuideAssignee: Joshua Wulf <jwulf>
Status: CLOSED CURRENTRELEASE QA Contact: Petra Svobodová <psvobodo>
Severity: low Docs Contact:
Priority: unspecified    
Version: 2.0CC: chetan, freznice, iboverma, jskeoch, jwulf, lcarlon, psvobodo, syeghiay
Target Milestone: 2.2.3   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
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Fixed In Version: Doc Type: Bug Fix
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Last Closed: 2012-11-19 04:27:24 UTC Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 683503    
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Description Ken Giusti 2011-05-11 19:45:31 UTC
Description of problem:


MRG 2.0 Msg User's Guide, Chapter 6 Persistence, section 6.4 Determining Journal Size:

This section discusses methods for avoiding enqueue overflow scenarios:

<bite here>

Applications that use persistent queues must either prevent enqueue threshold exceptions, or respond appropriately when the exception occurs. Here are some ways an application might respond if it encounters such exceptions:

    *
      Pause to allow messages to be consumed from the queue, then reconnect and resume sending.
    *
      Publish using a different routing key, or change bindings to route to a different queue.
    *
      Perform some sort of load balancing that matches the rate of publishing with the rate of consuming. 

<un-bite here>

Users should be encouraged to user Producer Flow Control in order to prevent producers from overflowing a queue in the first place.  For example:

Applications that use persistent queues must either prevent enqueue threshold exceptions, or respond appropriately when the exception occurs.   Configuring producer flow control on a persistent queue will allow the queue to block producers when the queue is in danger of overflowing. See section <BLAH: Queues, Producer Flow Control>

However, if the number of producers cannot be determined when the queue is created, it is still possible to encounter an enqueue threshold exception.  Here are some ways an application might respond if it encounters such exceptions:

....

Comment 2 Joshua Wulf 2012-10-16 10:29:26 UTC
It was added to the section, along with a link to Producer Flow Control.

I've added an additional note at the beginning of the Section 5.3.4 "Preventative Design" [Topic 11980]

Comment 4 Petra Svobodová 2012-10-31 09:49:13 UTC
The recommendation to use producer flow control to match consumption and production and also the reference to the "Producer Flow Control" section were added into chapter 5.3.4 Determining Journal Size in Red Hat Enterprise MRG 2 Messaging Installation and Configuration Guide, edition 1.

--> VERIFIED

Comment 5 Cheryn Tan 2012-11-19 04:27:24 UTC
MRG Messaging 2.2.3 docs have been released as of 14 November 2012, the docs are now available on https://access.redhat.com/knowledge/docs/Red_Hat_Enterprise_MRG/