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https://issues.apache.org/jira/browse/PIG-965?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12784854#action_12784854
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Thejas M Nair commented on PIG-965:
-----------------------------------

Never mind the question above, I notice that you have mentioned that the second 
patch has "optimization 1,2 and dk.brics.automaton".



> PERFORMANCE: optimize common case in matches (PORegex)
> ------------------------------------------------------
>
>                 Key: PIG-965
>                 URL: https://issues.apache.org/jira/browse/PIG-965
>             Project: Pig
>          Issue Type: Improvement
>          Components: impl
>            Reporter: Thejas M Nair
>            Assignee: Ankit Modi
>
> Some frequently seen use cases of 'matches' comparison operator have follow 
> properties -
> 1. The rhs is a constant string . eg "c1 matches 'abc%' "
> 2. Regexes such that look for matching prefix , suffix etc are very common. 
> eg - "abc%', "%abc", '%abc%' 
> To optimize for these common cases , PORegex.java can be changed to -
> 1. Compile the pattern (rhs of matches) re-use it if the pattern string has 
> not changed. 
> 2. Use string comparisons for simple common regexes (in 2 above).
> The implementation of Hive like clause uses similar optimizations.

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