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https://issues.apache.org/jira/browse/DERBY-2911?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12529019
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Knut Anders Hatlen commented on DERBY-2911:
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I manually enabled the new buffer manager in modules.properties and ran
suites.All + derbyall. The number of test cases failing in suites.All is now 7,
of which 6 are expected failures in StatementPlanCacheTest mentioned in a
previous comment. The last JUnit failure is in ImportExportTest:client:
1) ImportExportTest:clientjava.sql.SQLException: Limitation: Record cannot be
updated or inserted due to lack of space on the page. Use the parameters
derby.storage.pageSize and/or derby.storage.pageReservedSpace to work around
this limitation.
In derbyall, 8 tests failed:
derbyall/derbyall.fail:unit/cacheService.unit
derbyall/storeall/storeall.fail:store/rollForwardRecovery.sql
derbyall/storeall/storeall.fail:store/backupRestore1.java
derbyall/storeall/storeall.fail:store/OnlineBackupTest1.java
derbyall/storeall/storeall.fail:unit/T_RawStoreFactory.unit
derbyall/storeall/storeall.fail:unit/T_b2i.unit
derbyall/storeall/storeall.fail:unit/recoveryTest.unit
derbyall/storeall/storeall.fail:store/RecoveryAfterBackup.java
All the failures in derbyall seem to happen because entries are left in the
cache in an invalid state if Cacheable.setIdentity() or
Cacheable.createIdentity() throws a StandardException. I will fix this by
removing the entries whose identity cannot be set/created.
> 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-entry-javadoc.diff, d2911-unused.diff, d2911-unused.stat,
> d2911perf.java
>
>
> 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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