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Posted to issues@calcite.apache.org by "Chunwei Lei (Jira)" <ji...@apache.org> on 2020/09/23 02:26:00 UTC
[jira] [Commented] (CALCITE-4241) Some improvements to metadata
query
[ https://issues.apache.org/jira/browse/CALCITE-4241?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17200474#comment-17200474 ]
Chunwei Lei commented on CALCITE-4241:
--------------------------------------
Fixed in [https://github.com/apache/calcite/commit/e7ac26d6ec083848531b456d2acf3f7f58a499b5.] Thank you for your PR, [~fan_li_ya]!
> Some improvements to metadata query
> -----------------------------------
>
> Key: CALCITE-4241
> URL: https://issues.apache.org/jira/browse/CALCITE-4241
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Reporter: Liya Fan
> Assignee: Liya Fan
> Priority: Minor
> Labels: pull-request-available
> Time Spent: 2h
> Remaining Estimate: 0h
>
> # For {{RelMdColumnUniqueness#areColumnsUnique(RelSubset, RelMetadataQuery,
> ImmutableBitSet, boolean)}}, we can return early as we encounter the first null.
> # For {{RelMdDistinctRowCount#getDistinctRowCount(Values, RelMetadataQuery,
> ImmutableBitSet, RexNode)}}, we can get the distinct row count accurately, instead of guessing that half of the elements are distinct.
> # {{RelMdUtil}}#{{areColumnsDefinitelyUniqueWhenNullsFiltered}} could be implemented in a more efficient way.
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