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From "Sergey Shelukhin (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HIVE-7617) optimize bytes mapjoin hash table read path wrt serialization, at least for common cases
Date Thu, 14 Aug 2014 00:46:12 GMT

     [ https://issues.apache.org/jira/browse/HIVE-7617?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Sergey Shelukhin updated HIVE-7617:
-----------------------------------

    Attachment: HIVE-7617.02.patch

Tiny changes.
I have done some perf testing on other queries and I think this patch should be ready for
review. [~gopalv]

> optimize bytes mapjoin hash table read path wrt serialization, at least for common cases
> ----------------------------------------------------------------------------------------
>
>                 Key: HIVE-7617
>                 URL: https://issues.apache.org/jira/browse/HIVE-7617
>             Project: Hive
>          Issue Type: Improvement
>            Reporter: Sergey Shelukhin
>            Assignee: Sergey Shelukhin
>         Attachments: HIVE-7617.01.patch, HIVE-7617.02.patch, HIVE-7617.patch, HIVE-7617.prelim.patch
>
>
> BytesBytes has table stores keys in the byte array for compact representation, however
that means that the straightforward implementation of lookups serializes lookup keys to byte
arrays, which is relatively expensive.
> We can either shortcut hashcode and compare for common types on read path (integral types
which would cover most of the real-world keys), or specialize hashtable and from BytesBytes...
create LongBytes, StringBytes, or whatever. First one seems simpler now.



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