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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: d2911-15.diff
d2911-14.diff
Attaching two new patches for review:
d2911-14.diff - rewrites the part of ClockPolicy.shrinkMe() that Øystein
mentioned in his comment 4e. It is not supposed to change the behaviour, only
make the relationship between the variables pos and index clearer.
d2911-15.diff - removes the method ClockPolicy.trimeMe() since it's only adding
complexity and doesn't have any real value (I think).
Derbyall and suites.All ran cleanly (except ManagementMBeanTest which has
failed for some time in the nightly regression tests too).
> 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, d2911-13.diff,
> d2911-14.diff, d2911-15.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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