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Posted to issues@drill.apache.org by "Aman Sinha (JIRA)" <ji...@apache.org> on 2015/10/06 20:42:27 UTC
[jira] [Commented] (DRILL-3901) Performance regression with doing
Explain of COUNT(*) over 100K files
[ https://issues.apache.org/jira/browse/DRILL-3901?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14945545#comment-14945545 ]
Aman Sinha commented on DRILL-3901:
-----------------------------------
I should add that the normal performance tests over TPCH sf100 don't show a regression probably because the number of files is relatively small. The performance test with 100K and more files is a manual test that we started tracking recently since Drill users are having hundreds of thousands of files.
> Performance regression with doing Explain of COUNT(*) over 100K files
> ---------------------------------------------------------------------
>
> Key: DRILL-3901
> URL: https://issues.apache.org/jira/browse/DRILL-3901
> Project: Apache Drill
> Issue Type: Bug
> Affects Versions: 1.1.0
> Reporter: Aman Sinha
> Assignee: Mehant Baid
>
> We are seeing a performance regression when doing an Explain of SELECT COUNT(*) over 100K files in a flat directory (no subdirectories) on latest master branch compared to a run that was done on Sept 26. Some initial details (I will have more later):
> {code}
> master branch on Sept 26
> No metadata cache: 71.452 secs
> With metadata cache: 15.804 secs
> Latest master branch
> No metadata cache: 110 secs
> With metadata cache: 32 secs
> {code}
> So, both cases show regression.
> [~mehant] and I took an initial look at this and it appears we might be doing the directory expansion twice.
>
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