[jira] [Commented] (IMPALA-6314) Add run time scalar subquery check for uncorrelated subqueries

["ASF subversion and git services (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/IMPALA-6314?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16457046#comment-16457046 ] 

ASF subversion and git services commented on IMPALA-6314:
---------------------------------------------------------

Commit 1e79f14798a8f742bbf17f79a4666627dcef3faf in impala's branch refs/heads/master from [~boroknagyz]
[ https://git-wip-us.apache.org/repos/asf?p=impala.git;h=1e79f14 ]

IMPALA-6314: Add run time scalar subquery check for uncorrelated subqueries

If a scalar subquery is used with a binary predicate,
or, used in an arithmetic expression, it must return
only one row/column to be valid. If this cannot be
guaranteed at parse time through a single row aggregate
or limit clause, Impala fails the query like such.

E.g., currently the following query is not allowed:
SELECT bigint_col
FROM alltypesagg
WHERE id = (SELECT id FROM alltypesagg WHERE id = 1)

However, it would be allowed if the query contained
a LIMIT 1 clause, or instead of id it was max(id).

This commit makes the example valid by introducing a
runtime check to test if the subquery returns a single
row. If the subquery returns more than one row, it
aborts the query with an error.

I added a new node type, called CardinalityCheckNode. It
is created during planning on top of the subquery when
needed, then during execution it checks if its child
only returns a single row.

I extended the frontend tests and e2e tests as well.

Change-Id: I0f52b93a60eeacedd242a2f17fa6b99c4fc38e06
Reviewed-on: http://gerrit.cloudera.org:8080/9005
Reviewed-by: Alex Behm <al...@cloudera.com>
Tested-by: Impala Public Jenkins <im...@cloudera.com>


> Add run time scalar subquery check for uncorrelated subqueries
> --------------------------------------------------------------
>
>                 Key: IMPALA-6314
>                 URL: https://issues.apache.org/jira/browse/IMPALA-6314
>             Project: IMPALA
>          Issue Type: Sub-task
>          Components: Backend, Frontend
>            Reporter: Tim Armstrong
>            Assignee: Zoltán Borók-Nagy
>            Priority: Major
>              Labels: planner, ramp-up, tpc-ds
>




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