[jira] [Comment Edited] (DRILL-4573) Zero copy LIKE, REGEXP_MATCHES, SUBSTR

["jean-claude (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/DRILL-4573?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15265318#comment-15265318 ] 

jean-claude edited comment on DRILL-4573 at 5/1/16 4:23 PM:
------------------------------------------------------------

I attached patch DRILL-4573-3

It fixes the issue reported DRILL-4645

The CharSequenceWrapper.toString() method was called.

I decided to in-line the Matcher.replaceAll() to avoid creating that String altogether.

Notice in the case there is nothing to replace I just re-use the input buffer.



was (Author: jccote):
I attached patch DRILL-4573-3

It fixes the issue reported DRILL-4645

The CharSequenceWrapper.toString() method was called.

I decided to in-line the Matcher.replaceAll() to avoid creating that String altogether.

Notice in the case there is nothing to replace I copy the input buffer into the output buffer. Can you confirm that is the best way to copy the input buffer into the output buffer?



> 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.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)