From derby-dev-return-49179-apmail-db-derby-dev-archive=db.apache.org@db.apache.org Tue Oct 02 13:57:15 2007 Return-Path: Delivered-To: apmail-db-derby-dev-archive@www.apache.org Received: (qmail 90652 invoked from network); 2 Oct 2007 13:57:14 -0000 Received: from hermes.apache.org (HELO mail.apache.org) (140.211.11.2) by minotaur.apache.org with SMTP; 2 Oct 2007 13:57:14 -0000 Received: (qmail 39844 invoked by uid 500); 2 Oct 2007 13:57:03 -0000 Delivered-To: apmail-db-derby-dev-archive@db.apache.org Received: (qmail 39812 invoked by uid 500); 2 Oct 2007 13:57:03 -0000 Mailing-List: contact derby-dev-help@db.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: Delivered-To: mailing list derby-dev@db.apache.org Received: (qmail 39802 invoked by uid 99); 2 Oct 2007 13:57:03 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 02 Oct 2007 06:57:03 -0700 X-ASF-Spam-Status: No, hits=-100.0 required=10.0 tests=ALL_TRUSTED X-Spam-Check-By: apache.org Received: from [140.211.11.4] (HELO brutus.apache.org) (140.211.11.4) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 02 Oct 2007 13:57:11 +0000 Received: from brutus (localhost [127.0.0.1]) by brutus.apache.org (Postfix) with ESMTP id D319C714209 for ; Tue, 2 Oct 2007 06:56:50 -0700 (PDT) Message-ID: <10773945.1191333410862.JavaMail.jira@brutus> Date: Tue, 2 Oct 2007 06:56:50 -0700 (PDT) From: "Knut Anders Hatlen (JIRA)" To: derby-dev@db.apache.org Subject: [jira] Updated: (DERBY-2911) Implement a buffer manager using java.util.concurrent classes In-Reply-To: <19242816.1183715524465.JavaMail.jira@brutus> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Virus-Checked: Checked by ClamAV on apache.org [ https://issues.apache.org/jira/browse/DERBY-2911?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Knut Anders Hatlen updated DERBY-2911: -------------------------------------- Attachment: d2911-7.diff Attaching a new patch (d2911-7.diff) which implements reuse of free holder objects if the maximum size of the cache has not been reached (it only touches one file - ClockPolicy.java). The patch fixes the failure in unit/T_RawStoreFactory.unit. I have also started the full regression test suite. The failure in T_RawStoreFactory is still a mystery to me. I ended up with scanning for free items backwards from the end of the clock. If the scan started from the beginning, the test would fail. I suspect that either the test does not test what it's supposed to test, or perhaps there is a bug somewhere, but since I see the same failure if I change the scan direction in the old buffer manager, I'm confident that the buffer manager is not the problem. > 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: d2911-1.diff, d2911-1.stat, d2911-2.diff, d2911-3.diff, d2911-4.diff, d2911-5.diff, d2911-6.diff, d2911-6.stat, d2911-7.diff, d2911-entry-javadoc.diff, d2911-unused.diff, d2911-unused.stat, d2911perf.java, perftest6.pdf > > > 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. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.