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https://issues.apache.org/jira/browse/DRILL-4573?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15264313#comment-15264313
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ASF GitHub Bot commented on DRILL-4573:
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Github user hsuanyi commented on the pull request:
https://github.com/apache/drill/pull/458#issuecomment-215801663
Hi @jcmcote,
I see. But can you do us a favor. Regex_replace()'s behavior changes after
your patch
https://issues.apache.org/jira/browse/DRILL-4645
Can you help fix this? And would you mind merging the missing piece with
the new patch?
> Zero copy LIKE, REGEXP_MATCHES, SUBSTR
> --------------------------------------
>
> Key: DRILL-4573
> URL: https://issues.apache.org/jira/browse/DRILL-4573
> Project: Apache Drill
> Issue Type: Improvement
> Reporter: jean-claude
> Priority: Minor
> Fix For: 1.7.0
>
> Attachments: DRILL-4573.patch.txt
>
>
> All the functions using the java.util.regex.Matcher are currently creating
> Java string objects to pass into the matcher.reset().
> However this creates unnecessary copy of the bytes and a Java string object.
> The matcher uses a CharSequence, so instead of making a copy we can create an
> adapter from the DrillBuffer to the CharSequence interface.
> Gains of 25% in execution speed are possible when going over VARCHAR of 36
> chars. The gain will be proportional to the size of the VARCHAR.
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