[jira] [Created] (OAK-6483) Segment-based composite node store performance degradation

["Tomek Rękawek (JIRA)" <ji...@apache.org>]

Tomek Rękawek created OAK-6483:
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             Summary: Segment-based composite node store performance degradation
                 Key: OAK-6483
                 URL: https://issues.apache.org/jira/browse/OAK-6483
             Project: Jackrabbit Oak
          Issue Type: Bug
          Components: composite
    Affects Versions: 1.7.4
            Reporter: Tomek Rękawek
            Priority: Critical
             Fix For: 1.8, 1.7.5


It seems that the OAK-4732 is not compatible with the composite node store using a segment node store as the main (writeable) store. The OAK-4732 measures how much does it usually take to apply commit hooks and merge the new root. However, the composite node store plugs into the commit hook and reads other node store states. As a result, it may take quite a while and the measured values are big. They are then used to tune the lock inside the LockBasedScheduler#getHeadNodeState() method. Since the times are big, the method also waits a long time for the semaphore before it gives up. This causes performance degradation.

The {{-Doak.scheduler.fetch.commitDelayQuantile=0}} parameter can be used to disable the OAK-4732.



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