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Posted to dev@hive.apache.org by "Phabricator (JIRA)" <ji...@apache.org> on 2013/03/26 09:25:18 UTC

[jira] [Updated] (HIVE-3562) Some limit can be pushed down to map stage

     [ https://issues.apache.org/jira/browse/HIVE-3562?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Phabricator updated HIVE-3562:
------------------------------

    Attachment: HIVE-3562.D5967.4.patch

navis updated the revision "HIVE-3562 [jira] Some limit can be pushed down to map stage".

  1. Used Heap for ORDER BY and Map for GROUP BY
  2. Added tests for spill/break
  3. Changed to use percentage for memory threshold

Reviewers: tarball, JIRA

REVISION DETAIL
  https://reviews.facebook.net/D5967

CHANGE SINCE LAST DIFF
  https://reviews.facebook.net/D5967?vs=24861&id=30483#toc

AFFECTED FILES
  common/src/java/org/apache/hadoop/hive/conf/HiveConf.java
  conf/hive-default.xml.template
  ql/build.xml
  ql/ivy.xml
  ql/src/java/org/apache/hadoop/hive/ql/exec/ExtractOperator.java
  ql/src/java/org/apache/hadoop/hive/ql/exec/ForwardOperator.java
  ql/src/java/org/apache/hadoop/hive/ql/exec/GroupByOperator.java
  ql/src/java/org/apache/hadoop/hive/ql/exec/Operator.java
  ql/src/java/org/apache/hadoop/hive/ql/exec/ReduceSinkOperator.java
  ql/src/java/org/apache/hadoop/hive/ql/exec/SelectOperator.java
  ql/src/java/org/apache/hadoop/hive/ql/exec/TopNHash.java
  ql/src/java/org/apache/hadoop/hive/ql/exec/TopNHashForGBY.java
  ql/src/java/org/apache/hadoop/hive/ql/io/HiveKey.java
  ql/src/java/org/apache/hadoop/hive/ql/optimizer/LimitPushdownOptimizer.java
  ql/src/java/org/apache/hadoop/hive/ql/optimizer/Optimizer.java
  ql/src/java/org/apache/hadoop/hive/ql/plan/ReduceSinkDesc.java
  ql/src/test/queries/clientpositive/limit_pushdown.q
  ql/src/test/results/clientpositive/limit_pushdown.q.out

To: JIRA, tarball, navis
Cc: njain

                
> Some limit can be pushed down to map stage
> ------------------------------------------
>
>                 Key: HIVE-3562
>                 URL: https://issues.apache.org/jira/browse/HIVE-3562
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Navis
>            Assignee: Navis
>            Priority: Trivial
>         Attachments: HIVE-3562.D5967.1.patch, HIVE-3562.D5967.2.patch, HIVE-3562.D5967.3.patch, HIVE-3562.D5967.4.patch
>
>
> Queries with limit clause (with reasonable number), for example
> {noformat}
> select * from src order by key limit 10;
> {noformat}
> makes operator tree, 
> TS-SEL-RS-EXT-LIMIT-FS
> But LIMIT can be partially calculated in RS, reducing size of shuffling.
> TS-SEL-RS(TOP-N)-EXT-LIMIT-FS

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