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From "James Taylor (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (PHOENIX-2666) Performance regression: Aggregate query with filter on table with multiple column families
Date Fri, 12 Feb 2016 04:03:18 GMT

    [ https://issues.apache.org/jira/browse/PHOENIX-2666?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15143998#comment-15143998
] 

James Taylor commented on PHOENIX-2666:
---------------------------------------

Looking at this closer, I don't think it's a regression. The prior Phoenix version would use
the default column family to determine the guideposts, essentially over chunking the query
based on the guidepost width (28 guideposts versus 12). So we'd be throwing more than 2x the
number of threads at it.

An interesting test (and one which PHOENIX-1312 targets) would be a query that targets a particular
range of data that may have high skew for the column being queried (versus even data distribution
for the default column family). In the prior version, Phoenix wouldn't take that into account,
but instead would use the guideposts based on the default column family. In the new version,
you'd get an equal distribution of work for each thread and hence better performance.

> Performance regression: Aggregate query with filter on table with multiple column families
> ------------------------------------------------------------------------------------------
>
>                 Key: PHOENIX-2666
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-2666
>             Project: Phoenix
>          Issue Type: Bug
>    Affects Versions: 4.7.0
>            Reporter: Mujtaba Chohan
>            Assignee: Thomas D'Silva
>             Fix For: 4.7.0
>
>
> In the test, table contains total of 6 columns with one column per column family.
> Running a query  {code}select count(*) from T where last_column < ?{code} is 4x slower
after commit for PHOENIX-1312 (https://git-wip-us.apache.org/repos/asf?p=phoenix.git;a=commit;h=3fdaecdaaa2a2f07070df67f861252fd44e338c3)



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