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https://issues.apache.org/jira/browse/CALCITE-3244?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16906038#comment-16906038
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Volodymyr Vysotskyi commented on CALCITE-3244:
----------------------------------------------
Thanks, [~benj641] for reporting this issue and [~julianhyde] for taking an
initial look.
Looks like the root cause why it fails in Drill is connected with the way how
Calcite decorrelates sub-queries of such type.
For the following test:
{code:java}
@Test public void testDecorrelateScalarSubQuery() throws Exception {
final String sql =
"select \n"
+ " (select count(t2.id) \n"
+ " from (values(1), (2)) t2(id) where t2.id = t1.id)\n"
+ " from (values(1), (2)) t1(id)";
checkSubQuery(sql).withLateDecorrelation(true).check();
}
{code}
Calcite will generate the following plan with {{LogicalCorrelate}} operator:
{noformat}
LogicalProject(EXPR$0=[$1])
LogicalCorrelate(correlation=[$cor0], joinType=[left], requiredColumns=[{0}])
LogicalValues(tuples=[[{ 1 }, { 2 }]])
LogicalAggregate(group=[{}], EXPR$0=[COUNT()])
LogicalFilter(condition=[=($0, $cor0.ID)])
LogicalValues(tuples=[[{ 1 }, { 2 }]])
{noformat}
But Drill does not support Correlate operator except the case when it
corresponds to lateral unnest so it was expected that RelDecorrelator will
rewrite the plan to remove correlate operator.
> Decorrelating sub-queries - Adding Implicit RowID support
> ---------------------------------------------------------
>
> Key: CALCITE-3244
> URL: https://issues.apache.org/jira/browse/CALCITE-3244
> Project: Calcite
> Issue Type: Improvement
> Affects Versions: 1.20.0
> Reporter: benj
> Priority: Major
>
> Some very useful type of requests currently failed with:
> {code:java}
> SYSTEM ERROR: UnsupportedOperationException: Adding Implicit RowID column is
> not supported for ValuesPrel operator
> {code}
> Examples from DRILL-7050:
> {code:sql}
> select t1.id,
> (select count(t2.id)
> from (
> select 1 as id
> union all
> select 2 as id
> ) t2 where t2.id = t1.id)
> from (
> select 1 as id
> union all
> select 2 as id
> ) t1
> {code}
> {code:sql}
> SELECT t,
> (SELECT count(*) FROM
> (SELECT split(r,' ') AS r FROM
> (SELECT sub.t AS r)) AS x
> ,LATERAL(SELECT $unnest AS u FROM unnest(x.r))
> /* WHERE ... */) t2
> FROM
> (SELECT 'unnest is useful' AS t) sub
> {code}
>
> _Please note that in 1.18 the error for these requests was:_
> {code:java}
> Error: PLAN ERROR: Cannot convert RexNode to equivalent Drill expression.
> RexNode Class: org.apache.calcite.rex.RexCorrelVariable, RexNode Digest: $cor0
> {code}
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