[jboss-dev-forums] [Design of Messaging on JBoss (Messaging/JBoss)] - Re: Paging discussion:

[timfox]

"clebert.suconic at jboss.com" wrote : I have started a WIKI for paging:
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  | http://wiki.jboss.org/wiki/JBossMessaging2Paging
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  | The basic idea is to have a FileBasedCollection where we store Messages, having an eviction cache based on watermark, and a FileBasedQueue for messageReferences.
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  | Both FileBasedQueue and FileBasedCollection would share the same implementations.
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  | I'll  use SequentialFile to access the disk, so if we decide to go AIO later we could easily change it.
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  | One thing I'm doing differently from what I suggested on the face2face meeting was regarding the MessageReferences.
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  | During the f2f I thought about not requiring a separated file for MessageReferences where those references would just be a pointer on the main DataFile. but then I realized that in some events the queue could eventually get out of order. (such as redelivers caused by rollbacks). So, on that case we need a separated data structure for MessageReferences.
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  | The wiki so far only has some ideas and requirements. I will update it as soon as I have some UML diagram.
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  | 

Can you elaborate more why you need different files for messages and message references? I found it hard to understand from your wiki.

Also I didn't really understand the part about indexes.

Some deeper explanation on the wiki would be good. I think it's currently quite hard to work out your intentions from that page, and how they differ from what was discussed in Paris.

Also, please can you create a new branch for this work?

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