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https://issues.apache.org/jira/browse/DERBY-2911?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Knut Anders Hatlen updated DERBY-2911:
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Attachment: d2911-12.diff
Attaching d2911-12.diff which addresses Øystein's comments 3a, 4a (indirectly,
since that code was removed), 4b and 4f. It makes
ReplacementPolicy.insertEntry() void since the return value is not used, it
simplifies the handling of small caches in ClockPolicy.rotateClock(), and it
factors out common code in ClockPolicy.rotateClock() and
ClockPolicy.shrinkMe(). This patch is not supposed to change the behaviour in
any way.
suites.All ran cleanly. I have also started derbyall and I will report back if
it fails.
> Implement a buffer manager using java.util.concurrent classes
> -------------------------------------------------------------
>
> Key: DERBY-2911
> URL: https://issues.apache.org/jira/browse/DERBY-2911
> Project: Derby
> Issue Type: Improvement
> Components: Performance, Services
> Affects Versions: 10.4.0.0
> Reporter: Knut Anders Hatlen
> Assignee: Knut Anders Hatlen
> Priority: Minor
> Attachments: cleaner.diff, cleaner.tar, d2911-1.diff, d2911-1.stat,
> d2911-10.diff, d2911-10.stat, d2911-11.diff, d2911-12.diff, d2911-2.diff,
> d2911-3.diff, d2911-4.diff, d2911-5.diff, d2911-6.diff, d2911-6.stat,
> d2911-7.diff, d2911-7a.diff, d2911-9.diff, d2911-9.stat, d2911-enable.diff,
> d2911-entry-javadoc.diff, d2911-unused.diff, d2911-unused.stat,
> d2911perf.java, derby-2911-8.diff, derby-2911-8.stat, perftest.diff,
> perftest.pdf, perftest.stat, perftest2.diff, perftest6.pdf, poisson_patch8.tar
>
>
> There are indications that the buffer manager is a bottleneck for some types
> of multi-user load. For instance, Anders Morken wrote this in a comment on
> DERBY-1704: "With a separate table and index for each thread (to remove latch
> contention and lock waits from the equation) we (...) found that
> org.apache.derby.impl.services.cache.Clock.find()/release() caused about 5
> times more contention than the synchronization in LockSet.lockObject() and
> LockSet.unlock(). That might be an indicator of where to apply the next push".
> It would be interesting to see the scalability and performance of a buffer
> manager which exploits the concurrency utilities added in Java SE 5.
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