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https://issues.apache.org/jira/browse/DRILL-4573?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15291576#comment-15291576
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ASF GitHub Bot commented on DRILL-4573:
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Github user jinfengni commented on the pull request:
https://github.com/apache/drill/pull/458#issuecomment-220393770
@jcmcote , I opened DRILL-4688 to track this incorrect regression. Please
use DRILL-4688 to submit either a patch or pull request to address this issue.
As part of the verification for this issue, QA plan to add a set of test
suite to cover the cases of multi-byte characters. Previously, there is no
such test coverage and hence we are not able to catch this regression.
> 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-4573-3.patch.txt, 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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