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https://issues.apache.org/jira/browse/DERBY-3734?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12606931#action_12606931
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Knut Anders Hatlen commented on DERBY-3734:
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+1
I don't think there's any need to limit the maximum value for this setting. On
some systems, you may exceed the maximum allowed number of open files if you
increase the size of the container cache too much, but that's not something we
need to worry about if we leave the default as it is today.
> Maximum value allowed for derby.storage.fileCacheSize (100) is too low for
> large system. Increase the maximum value and redocument the property.
> -------------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: DERBY-3734
> URL: https://issues.apache.org/jira/browse/DERBY-3734
> Project: Derby
> Issue Type: Bug
> Components: Performance
> Affects Versions: 10.3.3.0
> Environment: Derby 10.3.3
> Reporter: Stan Bradbury
>
> Increasing the value of the undocumented property:
> derby.storage.fileCacheSize improves Derby performance in our system but the
> maximum allowed value (100) is not large enough to accommodate our system.
> Our performance engineer reports:
> The following stack shows items being evicted from Derby's container cache.
> Extra debug code showed that the cache was at its maximum size (100), and
> that about 1 in 25 accesses to the cache was resulting in a miss (forcing
> another item to be evicted). Since this results in synchronous disk write,
> performance is bottlenecked on IO. Patching Derby to allow the cache to grow
> to 200 entries solved the performance problem.
> Performance is severely degraded. CPU utilization is low -- performance is
> IO bound. A sampling of stack dumps for the key thread consistently have the
> following methods at the top of the stack:
> at sun/nio/ch/FileChannelImpl.force0(Native Method)
> at sun/nio/ch/FileChannelImpl.force(FileChannelImpl.java:392(Compiled Code))
> at org/apache/derby/impl/io/DirRandomAccessFile4.sync(Bytecode PC:5(Compiled
> Code))
> at org/apache/derby/impl/store/raw/data/RAFContainer.writeRAFHeader(Bytecode
> PC:86(Compiled Code))
> at org/apache/derby/impl/store/raw/data/RAFContainer.clean(Bytecode
> PC:84(Compiled Code))
> at org/apache/derby/impl/services/cache/CachedItem.clean(Bytecode
> PC:7(Compiled Code))
> at org/apache/derby/impl/services/cache/Clock.rotateClock(Bytecode
> PC:7(Compiled Code))
> at org/apache/derby/impl/services/cache/Clock.findFreeItem(Bytecode
> PC:17(Compiled Code))
> at org/apache/derby/impl/services/cache/Clock.find(Bytecode PC:71(Compiled
> Code))
> at
> org/apache/derby/impl/store/raw/data/BaseDataFileFactory.openContainer(Bytecode
> PC:65(Compiled Code))
> at
> org/apache/derby/impl/store/raw/data/BaseDataFileFactory.openContainer(Bytecode
> PC:7(Compiled Code))
> at org/apache/derby/impl/store/raw/xact/Xact.openContainer(Bytecode
> PC:29(Compiled Code))
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