[jira] [Commented] (HIVE-7617) optimize bytes mapjoin hash table read path wrt serialization, at least for common cases

["Sergey Shelukhin (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-7617?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14093650#comment-14093650 ] 

Sergey Shelukhin commented on HIVE-7617:
----------------------------------------

https://reviews.apache.org/r/24587

> 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.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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