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https://issues.apache.org/jira/browse/HIVE-14573?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Gopal V updated HIVE-14573:
---------------------------
Resolution: Fixed
Fix Version/s: 2.2.0
Release Note: Vectorization: Implement StringExpr::find() (Teddy Choi,
reviewed by Gopal V)
Status: Resolved (was: Patch Available)
Pushed to master, thanks [~teddy.choi]
> Vectorization: Implement StringExpr::find()
> --------------------------------------------
>
> Key: HIVE-14573
> URL: https://issues.apache.org/jira/browse/HIVE-14573
> Project: Hive
> Issue Type: Bug
> Reporter: Gopal V
> Assignee: Teddy Choi
> Fix For: 2.2.0
>
> Attachments: HIVE-14573.2.patch, HIVE-15743.1.patch,
> HIVE-15743.2.patch
>
>
> Currently, the LIKE expression implementation is a dumb 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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