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https://issues.apache.org/jira/browse/DERBY-5068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13026773#comment-13026773
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Dag H. Wanvik commented on DERBY-5068:
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Good to understand! The patch adds some complexity by manually converting to
UTF-8 "manually" instead of using the Java libraries, though. If you think the
performance increase is worth the added complexity, it might be nice to add
some links which explains the logic. Does the logic work also if the string
contains surrogate pairs?
> Investigate increased CPU usage on client after introduction of UTF-8
> CcsidManager
> ----------------------------------------------------------------------------------
>
> Key: DERBY-5068
> URL: https://issues.apache.org/jira/browse/DERBY-5068
> Project: Derby
> Issue Type: Task
> Affects Versions: 10.7.1.1
> Reporter: Knut Anders Hatlen
> Attachments: d5068-1a.diff
>
>
> While looking at the performance graphs for the single-record select test
> during the last year -
> http://home.online.no/~olmsan/derby/perf/select_1y.html - I noticed that
> there was a significant increase (10-20%) in CPU usage per transaction on the
> client early in October 2010. To be precise, the increase seems to have
> happened between revision 1004381 and revision 1004794. In that period, there
> were three commits: two related to DERBY-4757, and one related to DERBY-4825
> (tests only).
> We should try to find out what's causing the increased CPU usage and see if
> there's some way to reduce it.
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