jean-claude created DRILL-4573:
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             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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