[jira] [Assigned] (CALCITE-783) Infer collation of Project using monotonicity

["Julian Hyde (JIRA)" <ji...@apache.org>]

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

Julian Hyde reassigned CALCITE-783:
-----------------------------------

    Assignee: Milinda Lakmal Pathirage  (was: Julian Hyde)

> Infer collation of Project using monotonicity
> ---------------------------------------------
>
>                 Key: CALCITE-783
>                 URL: https://issues.apache.org/jira/browse/CALCITE-783
>             Project: Calcite
>          Issue Type: Bug
>          Components: core
>            Reporter: Milinda Lakmal Pathirage
>            Assignee: Milinda Lakmal Pathirage
>         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 for 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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