[
https://issues.apache.org/jira/browse/OAK-7162?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16352269#comment-16352269
]
Andrei Dulceanu commented on OAK-7162:
--------------------------------------
Backported to 1.8 branch at r1823155.
> Race condition on revisions head between compaction and scheduler could
> result in skipped commit
> ------------------------------------------------------------------------------------------------
>
> Key: OAK-7162
> URL: https://issues.apache.org/jira/browse/OAK-7162
> Project: Jackrabbit Oak
> Issue Type: Bug
> Components: segment-tar
> Affects Versions: 1.8.0
> Reporter: Andrei Dulceanu
> Assignee: Andrei Dulceanu
> Priority: Blocker
> Labels: scalability
> Fix For: 1.9.0, 1.10, 1.8.2
>
> Attachments: OAK-7162-02.patch, OAK-7162-03.patch,
> OAK-7162-test.patch, OAK-7162.patch
>
>
> There is a race condition on {{TarRevisions#head}} between a running
> compaction trying to set the new head [0] and the scheduler doing the same
> after executing a specific commit [1]. If the compaction thread is first,
> then the head assignment in the scheduler will fail and not be re-attempted.
> IMO, the simple if statement should be changed to a while loop in which the
> head is refreshed and the commit is re-applied against the new head, before
> attempting again to set a new head in {{TarRevisions}}. This is somehow
> similar to what we previously had [2], but without the unneeded
> optimistic/pessimistic strategies involving tokens.
> [0]
> https://github.com/apache/jackrabbit-oak/blob/trunk/oak-segment-tar/src/main/java/org/apache/jackrabbit/oak/segment/file/FileStore.java#L764
> [1]
> https://github.com/apache/jackrabbit-oak/blob/trunk/oak-segment-tar/src/main/java/org/apache/jackrabbit/oak/segment/scheduler/LockBasedScheduler.java#L253
> [2]
> https://github.com/apache/jackrabbit-oak/blob/1.6/oak-segment-tar/src/main/java/org/apache/jackrabbit/oak/segment/SegmentNodeStore.java#L686
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
