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https://issues.apache.org/jira/browse/CAMEL-8010?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16129189#comment-16129189
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ASF GitHub Bot commented on CAMEL-8010:
---------------------------------------

GitHub user rajithapl opened a pull request:

    https://github.com/apache/camel/pull/1894

    CAMEL-8010:Locking the critical section to avoid race condition if Ag…

    …gregateTimeOutChecker also completes at the same time as Recover task

You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/rajithapl/camel CAMEL-8010_RaceCondition

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/camel/pull/1894.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #1894
    
----
commit 3f13fb36727cf488d3c5afeac1c84ef877514925
Author: Rajithamol <rlakshma...@mediaocean.com>
Date:   2017-08-16T18:10:30Z

    CAMEL-8010:Locking the critical section to avoid race condition if 
AggregateTimeOutChecker also completes at the same time as Recover task

----


> Race condition in AggregatorProcessor recovery sometimes causes duplicates 
> (still)
> ----------------------------------------------------------------------------------
>
>                 Key: CAMEL-8010
>                 URL: https://issues.apache.org/jira/browse/CAMEL-8010
>             Project: Camel
>          Issue Type: Bug
>          Components: camel-core
>    Affects Versions: 2.14.0
>            Reporter: Marc Carter
>
> CAMEL-6097 Patched a pretty clear race condition between the completion 
> thread (CT) and recovery thread (RT) but leaves several holes when exercised 
> with a Jdbc repository and a separate aggregation thread (AT).
> #1 is relevant to all repository backends.
> #2 only affects fully transactional backends
> I'm currently taking a look into this bug as its a show-stopper that 
> _persistent_ repositories actually *decreases* reliability. (Untested) 
> workaround is to add an in-memory idemptotentconsumer immediately after the 
> aggregation.
> Here AT starts and completes an aggregation between defensive copy and when 
> RT repo scanning starts. CT then confirms it (in memory (*)) before repo 
> scanning ends.
> || AT || RT || CT ||
> | | inProg COPY to inProgCopy | |
> | repo START x | |  |
> | | | repo REMOVE x |
> | | | <commit> |
> |  | | inProg ADD x |
> | | repo SCAN (sees x) | |
> | | | {color:red}process x{color} |
> | | | repo CONFIRM x |
> | | | inProg REMOVE x | 
> | | | <commit> |
> | | x not inProg or inProgCopy | |
> | | {color:red}process x{color} | |
> | | repo CONFIRM x | | Fails silently as this is doInTransactionWithoutResult 
> | | <commit> | |
> {noformat}SQLWarning ignored: SQL state '02000', error code '10000', message 
> [No row was found for FETCH, UPDATE or DELETE; or the result of a query is an 
> empty table.]{noformat}
> (*) Side note: inProgressExchanges is updated by a {{Synchronisation}} inside 
> the UOW so is immediately visible although any DB change may not be visible 
> for ages (in threading terms) as the entire transaction must commit first.



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