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From "Gopal V (JIRA)" <j...@apache.org>
Subject [jira] [Created] (HIVE-14573) Vectorization: Implement StringExpr::find()
Date Thu, 18 Aug 2016 20:28:20 GMT
Gopal V created HIVE-14573:
------------------------------

             Summary: Vectorization: Implement StringExpr::find() 
                 Key: HIVE-14573
                 URL: https://issues.apache.org/jira/browse/HIVE-14573
             Project: Hive
          Issue Type: Bug
            Reporter: Gopal V


Currently, the LIKE expression implementation is a dump StringExpr::equals() loop.

For an input of N bytes and a pattern of M bytes, this has the complexity of ((N-M)*M), which
is not an issue with small patterns or small inputs.

The pattern matching is currently optimized for matches, while in clickstream data the opposite
is true in general.

>From the common crawl data, the following run will go through the same

{code}
select count(1) from uservisits_orc_data where useragent like "%Opera%" and searchword LIKE
"%fruit%";
{code}



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