[
https://issues.apache.org/jira/browse/CALCITE-569?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14292156#comment-14292156
]
Vladimir Sitnikov commented on CALCITE-569:
-------------------------------------------
In fact, a collation trait on a Project is tricky.
I am not sure the user of Project is supposed to track collation trait and keep
the sortedness all the way up to the execution root.
Certain projections are just hard to implement with keeping the sort order
(e.g. RexOver window functions).
So, I believe we should know (or invent) how it supposed to work.
If we allow LogicalProject to shuffle the rows, then we should always nullify
collation trait of a project, and disable deduceCollation call from
createProject.
If LogicalProject is supposed to honor collation trait, then we should reset
the collation trait at leadt for projects with window functions.
[~julianhyde], we need your input.
> ArrayIndexOutOfBoundException when deducing collation
> -----------------------------------------------------
>
> Key: CALCITE-569
> URL: https://issues.apache.org/jira/browse/CALCITE-569
> Project: Calcite
> Issue Type: Bug
> Affects Versions: 1.0.0-incubating
> Reporter: Aman Sinha
> Assignee: Julian Hyde
> Attachments:
> 0001-CALCITE-569-Create-a-Project-with-empty-collation-if.patch,
> 0001-Properly-track-collation-trait-for-select-a-from-.-o.patch,
> PlanTest.java.diff
>
>
> If a subquery has an ORDER BY on a column that is not in the SELECT list and
> the outer query does another ORDER BY, Calcite encounters an
> ArrayIndexOutOfBoundException when deducing collation.
> In PlannerTest, I created a simple test by first adding the following traits:
> {code}
> List<RelTraitDef> traitDefs = new ArrayList<RelTraitDef>();
> traitDefs.add(ConventionTraitDef.INSTANCE);
> traitDefs.add(RelCollationTraitDef.INSTANCE);
> {code}
> And ran the following query:
> {code}
> select t.psPartkey from (select ps.psPartkey from `tpch`.`partsupp` ps order
> by ps.psSupplyCost) t order by t.psPartkey"
> {code}
> {code}
> java.lang.ArrayIndexOutOfBoundsException: -1
> at
> org.apache.calcite.rex.RexProgram.deduceCollations(RexProgram.java:589)
> at org.apache.calcite.rex.RexProgram.getCollations(RexProgram.java:558)
> at
> org.apache.calcite.plan.RelOptUtil.createProject(RelOptUtil.java:2685)
> at
> org.apache.calcite.plan.RelOptUtil.createProject(RelOptUtil.java:2623)
> at
> org.apache.calcite.sql2rel.SqlToRelConverter.convertSelectList(SqlToRelConverter.java:3571)
> at
> org.apache.calcite.sql2rel.SqlToRelConverter.convertSelectImpl(SqlToRelConverter.java:613)
> at
> org.apache.calcite.sql2rel.SqlToRelConverter.convertSelect(SqlToRelConverter.java:568)
> at
> org.apache.calcite.sql2rel.SqlToRelConverter.convertQueryRecursive(SqlToRelConverter.java:2929)
> at
> org.apache.calcite.sql2rel.SqlToRelConverter.convertQuery(SqlToRelConverter.java:526)
> at org.apache.calcite.prepare.PlannerImpl.convert(PlannerImpl.java:189)
> {code}
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
