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From "Knut Anders Hatlen (JIRA)" <j...@apache.org>
Subject [jira] Updated: (DERBY-2911) Implement a buffer manager using java.util.concurrent classes
Date Mon, 14 Jan 2008 16:01:44 GMT

     [ https://issues.apache.org/jira/browse/DERBY-2911?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Knut Anders Hatlen updated DERBY-2911:
--------------------------------------

    Attachment: perftest.stat
                perftest.diff

The attached patch merges the test clients used previously in this issue and places them under
org.apache.derbyTesting.perf.clients. With the class Runner in that package, one can start
each of the tests from the command line and configure which type of load generator (back-to-back
or Poisson) to use.

I am currently running tests which compare the performance of ConcurrentCache and Clock on
one dual-CPU machine and on one 8-CPU machine. I'll post the results once I have them.

> 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, d2911-2.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-entry-javadoc.diff,
d2911-unused.diff, d2911-unused.stat, d2911perf.java, derby-2911-8.diff, derby-2911-8.stat,
perftest.diff, perftest.stat, 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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