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https://issues.apache.org/jira/browse/HIVE-1694?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12927077#action_12927077
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John Sichi edited comment on HIVE-1694 at 11/1/10 2:30 PM:
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+1 to what Namit said. Doing the rewrites at the relational algebra Operator
level (similar to the way optimizer transformations such as predicate pushdown
already work) will have two big advantages:
* more general (syntax-independent)
* much easier to maintain (as you noted in your presentation, the
SemanticAnalyzer data structures can be very difficult to analyze and
manipulate, whereas the Operator structures are a lot cleaner)
BTW, thanks for the very clear explanation of the work you've done so far.
was (Author: jvs):
+1 to what Namit said. Doing the rewrites at the relational algebra
Operator level (similar to the way optimizer transformations such as predicate
pushdown already work) will have two big advantages:
* more general (syntax-independent)
* much easier to maintain (as you noted in your presentation, the
SemanticAnalyzer data structures can be very difficult to analyze and
manipulate, whereas the Operator tree are a lot cleaner)
BTW, thanks for the very clear explanation of the work you've done so far.
> 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
> Attachments: demo_q1.hql, demo_q2.hql, HIVE-1694_2010-10-28.diff
>
>
> 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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