[jira] [Updated] (CALCITE-783) Project's collation infering logic doesn't handle monotonic expressions

["Milinda Lakmal Pathirage (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CALCITE-783?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Milinda Lakmal Pathirage updated CALCITE-783:
---------------------------------------------
    Attachment: CALCITE-783-0.patch

This patch doesn't handle all the corner cases. But created this to get Calcite community's feedback to know whether this approach is correct or not.

> Project's collation infering logic doesn't handle monotonic expressions
> -----------------------------------------------------------------------
>
>                 Key: CALCITE-783
>                 URL: https://issues.apache.org/jira/browse/CALCITE-783
>             Project: Calcite
>          Issue Type: Bug
>          Components: core
>            Reporter: Milinda Lakmal Pathirage
>            Assignee: Julian Hyde
>         Attachments: CALCITE-783-0.patch
>
>
> Current implementation of RelMdCollation#project doesn't handle function expressions and because of that we loose any collation metadata related to monotonic expressions which can be useful generating streaming query execution plans involving tumbling windows.
> Following is how current code looks like (RelMdCollation):
> 185: for (Ord<RexNode> project : Ord.zip(projects)) {
> 186:       if (project.e instanceof RexInputRef) {
> 187:         targets.put(((RexInputRef) project.e).getIndex(), project.i);
> 188:       } 
> 189: }
> We only handle projects of type RexInputRef. But to support monotonic expressions we should laso handle projects of type RexCall.



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