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https://issues.apache.org/jira/browse/AMQ-7082?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16676763#comment-16676763
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ASF subversion and git services commented on AMQ-7082:
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Commit 45d7676bd95a7e4594a80b025994ea3242c94586 in activemq's branch 
refs/heads/activemq-5.15.x from [~alanprot]
[ https://git-wip-us.apache.org/repos/asf?p=activemq.git;h=45d7676 ]

AMQ-7082 - Make sure that the recovery will only mark pages as free if they 
were created in a previous execution

(cherry picked from commit 0d34338919edee863bd71693ee30999d9d9d6ce9)


> KahaDB index, recover free pages in parallel with start
> -------------------------------------------------------
>
>                 Key: AMQ-7082
>                 URL: https://issues.apache.org/jira/browse/AMQ-7082
>             Project: ActiveMQ
>          Issue Type: Bug
>          Components: KahaDB
>    Affects Versions: 5.15.0
>            Reporter: Gary Tully
>            Assignee: Gary Tully
>            Priority: Major
>             Fix For: 5.16.0, 5.15.8
>
>
> AMQ-6590 fixes free page loss through recovery. The recover process can be 
> timely, which prevents fast failover, doing recovery on shutdown is 
> preferable, but it is still not ideal b/c it will hold onto the kahadb lock. 
> It also can stall shutdown unexpectedly.
> AMQ-7080 is going to tackle checkpointing the free list. This should help 
> avoid the need for recovery but it may still be necessary. If the perf hit is 
> significant this may need to be optional.
> There will still be the need to walk the index to find the free list.
> It is possible to run with no free list and grow, and we can do that while we 
> recover the free list in parallel, then merge the two at a safe point. This 
> we can do at startup.
> In cases where the disk is the bottleneck this won't help much, but it will 
> help failover and it will help shutdown, with a bit of luck the recovery will 
> complete before we stop.
>  
> Initially I thought this would be too complex, but if we concede some growth 
> while we recover, ie: start with an empty free list, it is should be straight 
> forward to merge with a recovered one.



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