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From "jean-claude (JIRA)" <j...@apache.org>
Subject [jira] [Created] (DRILL-4573) Zero copy LIKE, REGEXP_MATCHES, SUBSTR
Date Sat, 02 Apr 2016 02:38:25 GMT
jean-claude created DRILL-4573:

             Summary: 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

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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