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https://issues.apache.org/jira/browse/AMQ-7067?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16643123#comment-16643123
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Gary Tully commented on AMQ-7067:
---------------------------------
[~jgoodyear] I have pushed your changes and some additional test tidy up and a
prepare variant. Thank you.
[https://github.com/apache/activemq/commit/57c7939534a927bfc2d1b0454aac7ef8d804532b]
I think ack compaction will need some follow on work b/c it won't be aware that
the ackMessageFileMap now also has transaction locations, it will only move
acks and I think will leave the journals candidates for gc again.
As it stands ackCompaction should be disabled for this fix to be effective,
until that is proven not to be the case or it is fixed.
There are some ackCompaction tests that can be combined with the recovery
checks to validate.
This issue should remain open till we get a resolution to that.
> KahaDB Recovery can experience a dangling transaction when prepare and commit
> occur on different data files.
> ------------------------------------------------------------------------------------------------------------
>
> Key: AMQ-7067
> URL: https://issues.apache.org/jira/browse/AMQ-7067
> Project: ActiveMQ
> Issue Type: Bug
> Components: KahaDB, XA
> Affects Versions: 5.15.6
> Reporter: Jamie goodyear
> Priority: Critical
> Fix For: 5.16.0, 5.15.7
>
> Attachments: amq7067test.patch
>
>
> KahaDB Recovery can experience a dangling transaction when prepare and commit
> occur on different pagefiles.
> Scenario:
> A XA Transaction is started, message is prepared and sent into Broker.
> We then send into broker enough messages to file page file (100 message with
> 512 * 1024 characters in message payload). This forces a new pagefile to be
> created.
> Commit the XA transaction. Commit will land on the new page file.
> Restart the Broker.
> Upon restart a KahaDB recovery is executed.
> The prepare in PageFile 1 is not matched to Commit on PageFile 2, as such, it
> will appear in recovered message state.
> Looking deeper into this scenario, it appears that the commit message is
> GC'd, hence the prepare & commit can not be matched.
> The MessageDatabase only checks the following for GC:
> {color:#808080}// Don't GC files referenced by in-progress tx
> {color}{color:#cc7832}if {color}(inProgressTxRange[{color:#6897bb}0{color}]
> != {color:#cc7832}null{color}) {
> {color:#cc7832}for {color}({color:#cc7832}int
> {color}pendingTx=inProgressTxRange[{color:#6897bb}0{color}].getDataFileId(){color:#cc7832};
> {color}pendingTx <=
> inProgressTxRange[{color:#6897bb}1{color}].getDataFileId(){color:#cc7832};
> {color}pendingTx++) {
> gcCandidateSet.remove(pendingTx){color:#cc7832};
> {color} }
> }
> We need to become aware of where the prepare & commits occur in pagefiles
> with respect to GCing files.
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