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Posted to dev@hive.apache.org by "Prajakta Kalmegh (JIRA)" <ji...@apache.org> on 2011/03/03 16:21:37 UTC

[jira] Commented: (HIVE-1694) Accelerate GROUP BY execution using indexes

    [ https://issues.apache.org/jira/browse/HIVE-1694?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13002017#comment-13002017 ] 

Prajakta Kalmegh commented on HIVE-1694:
----------------------------------------

Hi John

We have made all the changes as suggested by you except for making the code pluggable (so that the rewrite expression changes depending on which index handler is used). We will submit this change along with the patch for new index type. 

We have started working on the new index type creation as per your suggestion and will let you know once that is complete. 

> Accelerate GROUP BY execution using indexes
> -------------------------------------------
>
>                 Key: HIVE-1694
>                 URL: https://issues.apache.org/jira/browse/HIVE-1694
>             Project: Hive
>          Issue Type: New Feature
>          Components: Indexing, Query Processor
>    Affects Versions: 0.7.0
>            Reporter: Nikhil Deshpande
>            Assignee: Prajakta Kalmegh
>         Attachments: HIVE-1694.1.patch.txt, HIVE-1694.2.patch.txt, HIVE-1694_2010-10-28.diff, demo_q1.hql, demo_q2.hql
>
>
> The index building patch (Hive-417) is checked into trunk, this JIRA issue tracks supporting indexes in Hive compiler & execution engine for SELECT queries.
> This is in ref. to John's comment at
> https://issues.apache.org/jira/browse/HIVE-417?focusedCommentId=12884869&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#action_12884869
> on creating separate JIRA issue for tracking index usage in optimizer & query execution.
> The aim of this effort is to use indexes to accelerate query execution (for certain class of queries). E.g.
> - Filters and range scans (already being worked on by He Yongqiang as part of HIVE-417?)
> - Joins (index based joins)
> - Group By, Order By and other misc cases
> The proposal is multi-step:
> 1. Building index based operators, compiler and execution engine changes
> 2. Optimizer enhancements (e.g. cost-based optimizer to compare and choose between index scans, full table scans etc.)
> This JIRA initially focuses on the first step. This JIRA is expected to hold the information about index based plans & operator implementations for above mentioned cases. 

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