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https://issues.apache.org/jira/browse/CALCITE-1234?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16514637#comment-16514637
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ASF GitHub Bot commented on CALCITE-1234:
-----------------------------------------
Github user F21 commented on the issue:
https://github.com/apache/calcite-avatica-go/pull/24
@kenshaw Thanks, this is a good idea! As this project is now part of the
Apache Calcite project and the change is not trivial, can you please do the
following:
- Open an issue in JIRA and set the component to `avatica-go`:
https://issues.apache.org/jira/projects/CALCITE/issues
- Update your commit message to reflect the JIRA issue number and include
your name, ex: `[CALCITE-1234] Change UUID package to
github.com/hashicorp/go-uuid (Ken Shaw)`
Thanks! 😄
> Annotate table functions to allow pushing down project, filter
> --------------------------------------------------------------
>
> Key: CALCITE-1234
> URL: https://issues.apache.org/jira/browse/CALCITE-1234
> Project: Calcite
> Issue Type: Bug
> Reporter: Julian Hyde
> Assignee: Julian Hyde
> Priority: Major
>
> In general it is not possible to push relational operators through table
> functions but many table functions have properties that will allow push down:
> for instance, they might preserve fields, preserve row count, return rows in
> the same order. If we annotate a table function with these properties, we can
> automatically push down a Filter, and so forth.
> Some ideas:
> * {{PreservesFieldNames}}: If an output field has the same name as an input
> field, it is assumed to be the same field.
> * {{PreservesRows}}: Each input row causes exactly one output row, in the
> same order.
> * {{FiltersRows}}: Each input row causes at most one output row, in the same
> order.
> * {{PreservesFieldPositions}}: The leading N columns of the output are
> equivalent to the leading N columns of the input.
> If {{(PreservesFieldNames or PreservesFieldPositions) and (PreservesRows or
> FiltersRows)}}, it is safe to push down a Filter if all of the fields of the
> predicate exist in the input.
> Similarly pushing down a Project; and we can push down an Aggregate if
> {{PreservesRows}}.
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