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Posted to issues@drill.apache.org by "ASF GitHub Bot (JIRA)" <ji...@apache.org> on 2016/02/26 22:51:18 UTC
[jira] [Commented] (DRILL-4449) Wrong results when using metadata
cache with specific set of queries
[ https://issues.apache.org/jira/browse/DRILL-4449?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15169903#comment-15169903 ]
ASF GitHub Bot commented on DRILL-4449:
---------------------------------------
GitHub user adeneche opened a pull request:
https://github.com/apache/drill/pull/392
DRILL-4449: Wrong results when metadata cache is used with specific s…
…et of queries
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/adeneche/incubator-drill DRILL-4449
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/drill/pull/392.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 #392
----
commit 38c346e6c638f9a2aafeef932b5e78885368064b
Author: adeneche <ad...@gmail.com>
Date: 2016-02-25T03:19:09Z
DRILL-4449: Wrong results when metadata cache is used with specific set of queries
----
> Wrong results when using metadata cache with specific set of queries
> --------------------------------------------------------------------
>
> Key: DRILL-4449
> URL: https://issues.apache.org/jira/browse/DRILL-4449
> Project: Apache Drill
> Issue Type: Bug
> Components: Storage - Parquet
> Affects Versions: 1.5.0
> Reporter: Deneche A. Hakim
> Priority: Critical
> Fix For: 1.6.0
>
>
> We are still working on a reproduction but when we have a query similar to this one:
> {noformat}
> with q1 as (
> select a.field
> from `table` a
> where <some condition that causes the table to be pruned>
> group by a.field
> having ...
> )
> , q2 as (
> select a.field
> from `table` a
> where <some other pruning condition>
> group by a.field
> )
> select * from (
> select count(*) as cnt from q1
> union all
> select count(*) as cnt from q2
> );
> {noformat}
> The table is partitioned and both sub queries will force a parquet pruning on the table. Because we share the parquet metadata object in ParquetGroupScan, the second query end up being "over pruned" and we get wrong results.
> The plan doesn't show the problem.
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