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https://issues.apache.org/jira/browse/OAK-4732?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16074435#comment-16074435
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Michael Dürig commented on OAK-4732:
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Patch looks good to me. Maybe we increase the
{{SynchronizedDescriptiveStatistics}} window a bit? 1000 instead of 100?
As a follow up, it would be good to add a feature flag to control this feature
if this turns out to be necessary. One way would be to add a flag to configure
the percentile used in {{LockBasedScheduler.getHeadNodeState()}}. Setting it to
{{0}} would basically disable this. Setting it to a different value might be
interesting in future experiments.
> (Slightly) prioritise reads over writes
> ----------------------------------------
>
> Key: OAK-4732
> URL: https://issues.apache.org/jira/browse/OAK-4732
> Project: Jackrabbit Oak
> Issue Type: Improvement
> Components: segment-tar
> Reporter: Michael Dürig
> Assignee: Andrei Dulceanu
> Priority: Minor
> Labels: Performance, scalability
> Fix For: 1.8, 1.7.4
>
> Attachments: OAK-4732.patch
>
>
> When fetching the current root from the {{SegmentNodeStore}} an older
> revision will be returned when a commit is being processed concurrently. I
> think it would make sense to wait for a short time in this case increasing
> the chance of returning an up to date state. The idea is that this would
> lower the rebasing work that need to be done later on should the returned
> root be used for further modifications.
> An interesting value for the wait time is to use the median (or more general
> a percentile) of the commit time of the last say 1000 commits. This would
> mean that (for the median) we have a 50% chance of getting up to date date.
> For a 90% percentile we would have longer wait times but then a 90% chance of
> getting up to date date.
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