[
https://issues.apache.org/jira/browse/TRAFODION-2259?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15812856#comment-15812856
]
ASF GitHub Bot commented on TRAFODION-2259:
-------------------------------------------
GitHub user prashanth-vasudev opened a pull request:
https://github.com/apache/incubator-trafodion/pull/907
[TRAFODION-2259] Add TopN stats counter and realign BMO stats.
As part of TopN sort feature , adding a stats entry to represent Topn.
Also realigned the bmo stats columns for uniform display.
See LOGRTS file for a sample output.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/prashanth-vasudev/incubator-trafodion topn
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/incubator-trafodion/pull/907.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #907
----
commit 271a5d0e656dc467453381416c261dda5c3411b0
Author: Prashant Vasudev <[email protected]>
Date: 2017-01-09T21:07:18Z
[TRAFODION-2259] Add TopN stats counter and realign BMO stats.
----
> Sort TopN operator
> ------------------
>
> Key: TRAFODION-2259
> URL: https://issues.apache.org/jira/browse/TRAFODION-2259
> Project: Apache Trafodion
> Issue Type: Improvement
> Components: sql-exe
> Affects Versions: 2.1-incubating
> Reporter: Prashanth Vasudev
> Assignee: Prashanth Vasudev
>
> Sort operator consumes all records before producing sorted records. For
> certain use cases where only Top N records are required, today sort consumes
> all records into memory and overflows( spills ) to disk. This impacts
> performance.
> if topN is pushed down to sort, only required memory can be allocated and
> sort would only hold topN records in memory. Once all the records are read,
> sorted records in topN is returned.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
