You are viewing a plain text version of this content. The canonical link for it is here.
Posted to issues@drill.apache.org by "Julian Hyde (JIRA)" <ji...@apache.org> on 2016/12/01 02:36:59 UTC
[jira] [Commented] (DRILL-2543) Correlated subquery where outer
table contains NULL values returns seemingly wrong result
[ https://issues.apache.org/jira/browse/DRILL-2543?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15710628#comment-15710628 ]
Julian Hyde commented on DRILL-2543:
------------------------------------
[~jni], did you ever log a Calcite issue for this? CALCITE-1513 is looking similar.
> Correlated subquery where outer table contains NULL values returns seemingly wrong result
> ------------------------------------------------------------------------------------------
>
> Key: DRILL-2543
> URL: https://issues.apache.org/jira/browse/DRILL-2543
> Project: Apache Drill
> Issue Type: Bug
> Components: Query Planning & Optimization
> Affects Versions: 0.8.0
> Reporter: Victoria Markman
> Assignee: Jinfeng Ni
> Priority: Critical
> Fix For: Future
>
>
> {code}
> 0: jdbc:drill:schema=dfs> select * from t1;
> +------------+------------+------------+
> | a1 | b1 | c1 |
> +------------+------------+------------+
> | 1 | 2015-03-01 | aaaaa |
> | 2 | 2015-03-02 | bbbbb |
> | null | null | null |
> +------------+------------+------------+
> 3 rows selected (0.064 seconds)
> 0: jdbc:drill:schema=dfs> select * from t2;
> +------------+------------+------------+
> | a2 | b2 | c2 |
> +------------+------------+------------+
> | 5 | 2017-03-01 | a |
> +------------+------------+------------+
> 1 row selected (0.07 seconds)
> 0: jdbc:drill:schema=dfs> select t1.c1, count(*) from t1 where t1.b1 not in (select b2 from t2 where t1.a1 = t2.a2) group by t1.c1 order by t1.c1;
> +------------+------------+
> | c1 | EXPR$1 |
> +------------+------------+
> | aaaaa | 1 |
> | bbbbb | 1 |
> +------------+------------+
> 2 rows selected (0.32 seconds)
> {code}
> Postgres returns row from the outer table where a1 is null.
> This is part that I don't understand, because join condition in the subquery should have eliminated row where a1 IS NULL. To me Drill result looks correct. Unless there is something different in correlated comparison semantics that I'm not aware of.
> {code}
> postgres=# select * from t1;
> a1 | b1 | c1
> ----+------------+-------
> 1 | 2015-03-01 | aaaaa
> 2 | 2015-03-02 | bbbbb
> | |
> (3 rows)
> {code}
> Explain plan for the query:
> {code}
> 00-01 Project(c1=[$0], EXPR$1=[$1])
> 00-02 StreamAgg(group=[{0}], EXPR$1=[COUNT()])
> 00-03 Sort(sort0=[$0], dir0=[ASC])
> 00-04 Project(c1=[$0])
> 00-05 SelectionVectorRemover
> 00-06 Filter(condition=[NOT(IS TRUE($3))])
> 00-07 HashJoin(condition=[=($1, $2)], joinType=[left])
> 00-09 Project($f1=[$0], $f3=[$2])
> 00-11 SelectionVectorRemover
> 00-13 Filter(condition=[IS NOT NULL($1)])
> 00-15 Project(c1=[$1], b1=[$0], a1=[$2])
> 00-17 Scan(groupscan=[ParquetGroupScan [entries=[ReadEntryWithPath [path=maprfs:/test/t1]], selectionRoot=/test/t1, numFiles=1, columns=[`c1`, `b1`, `a1`]]])
> 00-08 Project($f02=[$1], $f2=[$2])
> 00-10 StreamAgg(group=[{0, 1}], agg#0=[MIN($2)])
> 00-12 Sort(sort0=[$0], sort1=[$1], dir0=[ASC], dir1=[ASC])
> 00-14 Project($f0=[$1], $f02=[$2], $f1=[true])
> 00-16 HashJoin(condition=[=($2, $0)], joinType=[inner])
> 00-18 StreamAgg(group=[{0}])
> 00-20 Sort(sort0=[$0], dir0=[ASC])
> 00-22 Project($f0=[$1])
> 00-23 SelectionVectorRemover
> 00-24 Filter(condition=[IS NOT NULL($0)])
> 00-25 Scan(groupscan=[ParquetGroupScan [entries=[ReadEntryWithPath [path=maprfs:/test/t1]], selectionRoot=/test/t1, numFiles=1, columns=[`b1`, `a1`]]])
> 00-19 Project(a2=[$1], b2=[$0])
> 00-21 Scan(groupscan=[ParquetGroupScan [entries=[ReadEntryWithPath [path=maprfs:/test/t2]], selectionRoot=/test/t2, numFiles=1, columns=[`a2`, `b2`]]])
> {code}
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)