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

["Prajakta Kalmegh (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-1694?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12989983#comment-12989983 ] 

Prajakta Kalmegh commented on HIVE-1694:
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Hi John,

We have the code ready for review. You can view it at <https://github.com/prafullat/hive/tree/prj>.
Please find attached the diff 'HIVE-1694.1.patch' for the changes. We have taken the diff from the github hive repo <https://github.com/apache/hive.git> on 30th Jan 2011. The last commit on github apache/hive before we took a diff was <https://github.com/apache/hive/commit/2cbbccc5fa9fe3bd9b0569021831f745fa1d4a06>.

Rewrite needs to be enabled explicitly by setting the 'hive.optimize.gbyusingindex' flag to true as done in 'ql_rewrite_gbtoidx.q' test case. We have added the 'ql_rewrite_gbtoidx.q' file in  ql/src/test/queries/clientpositive.


> Accelerate query 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: Nikhil Deshpande
>         Attachments: 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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