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https://issues.apache.org/jira/browse/DRILL-4875?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15468055#comment-15468055
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Sudheesh Katkam edited comment on DRILL-4875 at 9/6/16 6:08 PM:
----------------------------------------------------------------
Simply put, based on the [documented
model|http://drill.apache.org/docs/querying-complex-data-introduction/], the
initial query is _wrong_ for the expectations. Drill should have failed nicely,
instead of returning any results.
was (Author: sudheeshkatkam):
Simply put, based on the [documented
model|http://drill.apache.org/docs/querying-complex-data-introduction/], the
initial query is _wrong_ for the intended usage. Drill should have failed
nicely, instead of returning any results.
> select over array of maps returns incorrect results
> ---------------------------------------------------
>
> Key: DRILL-4875
> URL: https://issues.apache.org/jira/browse/DRILL-4875
> Project: Apache Drill
> Issue Type: Bug
> Components: Query Planning & Optimization
> Affects Versions: 1.9.0
> Environment: 4 node cluster CentOS
> Reporter: Khurram Faraaz
> Priority: Critical
>
> select over array of maps returns incorrect results
> Drill 1.9.0 git commit ID : 28d315bbb
> Data used in test
> {noformat}
> [test@centos-a ~]# cat arrayofmaps.json
> {"arr":[{"key":"a"},{"key":"b"},{"key":"c"},{"key":"d"}]}
> {noformat}
> Array elements are
> {noformat}
> 0: jdbc:drill:schema=dfs.tmp> select t.arr from `arrayofmaps.json` t;
> +----------------------------------------------------+
> | arr |
> +----------------------------------------------------+
> | [{"key":"a"},{"key":"b"},{"key":"c"},{"key":"d"}] |
> +----------------------------------------------------+
> 1 row selected (0.289 seconds)
> {noformat}
> The below query should return 4 rows, each row containing one value a,b,c and
> d respectively
> However query just returns only one value, which is not correct.
> {noformat}
> 0: jdbc:drill:schema=dfs.tmp> select t.arr.key from `arrayofmaps.json` t
> where t.arr.key is not null;
> +---------+
> | EXPR$0 |
> +---------+
> | a |
> +---------+
> 1 row selected (0.33 seconds)
> {noformat}
> Explain plan for above failing query
> {noformat}
> 0: jdbc:drill:schema=dfs.tmp> explain plan for select t.arr.key from
> `arrayofmaps.json` t where t.arr.key is not null;
> +------+------+
> | text | json |
> +------+------+
> | 00-00 Screen
> 00-01 Project(EXPR$0=[$0])
> 00-02 SelectionVectorRemover
> 00-03 Filter(condition=[IS NOT NULL($0)])
> 00-04 Project(ITEM=[ITEM($0, 'key')])
> 00-05 Scan(groupscan=[EasyGroupScan
> [selectionRoot=maprfs:/tmp/arrayofmaps.json, numFiles=1,
> columns=[`arr`.`key`], files=[maprfs:///tmp/arrayofmaps.json]]])
> {noformat}
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