[
https://issues.apache.org/jira/browse/CALCITE-900?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14934234#comment-14934234
]
Julian Hyde commented on CALCITE-900:
-------------------------------------
[~seanhychu], I agree, this is a problem.
[~jcamachorodriguez], Can you please review this and in particular the
trace.log that [~seanhychu] attached? It is similar to the problem you have
observed with looping when you push down LIMIT.
I don't want to make rules responsible for reining themselves in - otherwise we
will have to frequently re-engineer rules when they are combined with other
rules. In this case, I think the best solution might be to fire the rule if
there there is a trivial Project on a Union(all=true), but generate the same
Union. The latest RelBuilder.project does this automatically when it is given a
trivial project list.
> ProjectSetOpTransposeRule can be improved when the input is a SetOperator
> with Trivial Project on top
> -----------------------------------------------------------------------------------------------------
>
> Key: CALCITE-900
> URL: https://issues.apache.org/jira/browse/CALCITE-900
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Reporter: Sean Hsuan-Yi Chu
> Assignee: Julian Hyde
> Attachments: trace.log
>
>
> When SetOperator with Trivial Project on top, pushing this trivial project
> does not necessary. An improvement can be done if we just discard this
> trivial project.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
