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Posted to issues@drill.apache.org by "Khurram Faraaz (JIRA)" <ji...@apache.org> on 2015/05/05 00:45:06 UTC

[jira] [Reopened] (DRILL-2953) Group By + Order By query results are not ordered.

     [ https://issues.apache.org/jira/browse/DRILL-2953?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Khurram Faraaz reopened DRILL-2953:
-----------------------------------

> Group By + Order By query results are not ordered.
> --------------------------------------------------
>
>                 Key: DRILL-2953
>                 URL: https://issues.apache.org/jira/browse/DRILL-2953
>             Project: Apache Drill
>          Issue Type: Bug
>          Components: Query Planning & Optimization
>    Affects Versions: 0.9.0
>         Environment: 10833d2cae9f5312cf0e31f8c9f3f8a9dcdc0c45 | Commit 0.9.0 release version. | 03.05.2015 @ 14:56:56 EDT
>            Reporter: Khurram Faraaz
>            Assignee: Jinfeng Ni
>            Priority: Critical
>
> Group by + order by query does not return results in correct order. Sort is performed before the aggregation is done, which should not be the case.
> Test was performed on 4 node cluster on CentOS.
> {code}
> 0: jdbc:drill:> select cast(columns[0] as int) c1 from `testWindow.csv` t2 where t2.columns[0] is not null group by columns[0] order by columns[0];
> +------------+
> |     c1     |
> +------------+
> | 10         |
> | 100        |
> | 113        |
> | 119        |
> | 2          |
> | 50         |
> | 55         |
> | 57         |
> | 61         |
> | 67         |
> | 89         |
> +------------+
> 11 rows selected (0.218 seconds)
> {code}
> Explain plan for that query that returns wrong results.
> {code}
> 0: jdbc:drill:> explain plan for select cast(columns[0] as int) c1 from `testWindow.csv` t2 where t2.columns[0] is not null group by columns[0] order by columns[0];
> +------------+------------+
> |    text    |    json    |
> +------------+------------+
> | 00-00    Screen
> 00-01      Project(c1=[$0])
> 00-02        Project(c1=[CAST($0):INTEGER], EXPR$1=[$0])
> 00-03          StreamAgg(group=[{0}])
> 00-04            Sort(sort0=[$0], dir0=[ASC])
> 00-05              Filter(condition=[IS NOT NULL($0)])
> 00-06                Project(ITEM=[ITEM($0, 0)])
> 00-07                  Scan(groupscan=[EasyGroupScan [selectionRoot=/tmp/testWindow.csv, numFiles=1, columns=[`columns`[0]], files=[maprfs:/tmp/testWindow.csv]]])
> {code} 
> Incorrect results , not in order.
> {code}
> 0: jdbc:drill:> select cast(columns[0] as int) from `testWindow.csv` t2 where t2.columns[0] is not null group by columns[0] order by columns[0];
> +------------+
> |   EXPR$0   |
> +------------+
> | 10         |
> | 100        |
> | 113        |
> | 119        |
> | 2          |
> | 50         |
> | 55         |
> | 57         |
> | 61         |
> | 67         |
> | 89         |
> +------------+
> 11 rows selected (0.214 seconds)
> {code}



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