[jira] [Work logged] (HIVE-26072) Enable vectorization for stats gathering (tablescan op)

["ASF GitHub Bot (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HIVE-26072?focusedWorklogId=747614&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-747614 ]

ASF GitHub Bot logged work on HIVE-26072:
-----------------------------------------

                Author: ASF GitHub Bot
            Created on: 25/Mar/22 05:21
            Start Date: 25/Mar/22 05:21
    Worklog Time Spent: 10m 
      Work Description: ayushtkn opened a new pull request #3142:
URL: https://github.com/apache/hive/pull/3142


   After https://issues.apache.org/jira/browse/HIVE-23530 , almost all compute stats functions are vectorizable. Only function that is not vectorizable is "compute_bit_vector" for ndv statistics computation. This causes "create table as select" and "insert overwrite select" queries to run in non-vectorized mode. 
   
   Even a very naive implementation of vectorized compute_bit_vector gives about 50% performance improvement on simple "insert overwrite select" queries. That is because entire mapper or reducer can run in vectorized mode.


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Issue Time Tracking
-------------------

            Worklog Id:     (was: 747614)
    Remaining Estimate: 0h
            Time Spent: 10m

> Enable vectorization for stats gathering (tablescan op)
> -------------------------------------------------------
>
>                 Key: HIVE-26072
>                 URL: https://issues.apache.org/jira/browse/HIVE-26072
>             Project: Hive
>          Issue Type: Bug
>          Components: Hive
>            Reporter: Rajesh Balamohan
>            Assignee: Ayush Saxena
>            Priority: Major
>          Time Spent: 10m
>  Remaining Estimate: 0h
>
> https://issues.apache.org/jira/browse/HIVE-24510 enabled vectorization for compute_bit_vector. 
> But tablescan operator for stats gathering is disabled by default.
> [https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/optimizer/physical/Vectorizer.java#L2577]
> Need to enable vectorization for this. This can significantly reduce runtimes for analyze statements for large tables.



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