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https://issues.apache.org/jira/browse/OAK-4966?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Alex Parvulescu updated OAK-4966:
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Attachment: OAK-4966-jmx-notification.patch
attaching new patch based on the jmx notification mechanism. includes all
config options (jmx, osgi). I set the default at {{15%}}, not sure if this is
enough.
Left a TODO related to introducing a minimal value of available memory.
previous analysis showed that all caches with the current defaults can go over
{{2GB}}, so arguably it doesn't even make sense to run compaction if you don't
have at least that, otherwise you'd be racing agains the OOME notification,
which might not be a perfect way to prevent a crash.
The Felix issue is still pending, did not look into patching that yet.
[~mduerig] feedback appreciated!
> Re-introduce a blocker for compaction based on available heap
> -------------------------------------------------------------
>
> Key: OAK-4966
> URL: https://issues.apache.org/jira/browse/OAK-4966
> Project: Jackrabbit Oak
> Issue Type: Improvement
> Components: segment-tar
> Reporter: Alex Parvulescu
> Assignee: Alex Parvulescu
> Fix For: 1.6, 1.5.13
>
> Attachments: OAK-4966-jmx-notification.patch, OAK-4966.patch
>
>
> As seen in a local test, running compaction on a tight heap can lead to
> OOMEs. There used to be a best effort barrier against this situation 'not
> enough heap for compaction', but we removed it with the compaction maps.
> I think it makes sense to add it again based on the max size of some of the
> caches: segment cache {{256MB}} by default [0] and some writer caches which
> can go up to {{2GB}} all combined [1] and probably others I missed.
> [0]
> https://github.com/apache/jackrabbit-oak/blob/trunk/oak-segment-tar/src/main/java/org/apache/jackrabbit/oak/segment/SegmentCache.java#L48
> [1]
> https://github.com/apache/jackrabbit-oak/blob/trunk/oak-segment-tar/src/main/java/org/apache/jackrabbit/oak/segment/WriterCacheManager.java#L50
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