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https://issues.apache.org/jira/browse/JENA-256?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13418326#comment-13418326
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Andy Seaborne commented on JENA-256:
------------------------------------
The codebase only has the optimization on. It requires a code change to set it
to zero batch size.
The batch size is set in TransactionManager.TSM_WriteBackEndTxn.QueueBatchSize
to 10.
More than 10 didn't make a great deal of difference.
Ideally, flush-back would all handled on another thread - batching is a
cautious step in thet direction.
I used;
apache-jena-2.7.3-20120718.212752-16.zip
and the development codebase.
It is conceivable that it was not in the first 7/18 build because of Jenkins
overload.
If that does not make a difference, it is worth trying your example code with a
singe read transaction around the whole loop. This causes a similar effect
even in the old code.
> Significant performance regression (TDB?) on 2.7.1 RC compared to May 15 build
> ------------------------------------------------------------------------------
>
> Key: JENA-256
> URL: https://issues.apache.org/jira/browse/JENA-256
> Project: Apache Jena
> Issue Type: Bug
> Components: TDB
> Affects Versions: Jena 2.7.1
> Environment: Windows 7, 64 bit, tested against 2.7.1 RC from June 9
> versus a build from May 15
> Reporter: Simon Helsen
> Assignee: Andy Seaborne
> Priority: Critical
> Fix For: TDB 0.9.3
>
> Attachments: 271May15Output1.txt, 271May15Output2.txt,
> 271May15Output3.txt, 271May15Output4.txt, 271RCOutput1.txt, 271RCOutput2.txt,
> 271RCOutput3.txt, 271RCOutput4.txt, PerformanceRegressionTest.java
>
>
> See also
> http://mail-archives.apache.org/mod_mbox/jena-dev/201206.mbox/%3C4FD9F19E.3080904%40bristol.ac.uk%3E
> I was able to reproduce the performance regression with an isolated test
> scenario. So I recreated the components ARQ, CORE, IRI, and TDB with the SVN
> state of May 15 9 (so svn update -r {2012-05-15} and then svn clean install)
> I then created a simple test program (attached as
> PerformanceRegressionTest.java) which I ran 4 times in a row for each version
> of Jena. Note that I deleted the TDB directory after the first 4 runs before
> using the other Jena version. Attached are the files with the output. The
> regression is obvious
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