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Posted to issues@calcite.apache.org by "Liya Fan (Jira)" <ji...@apache.org> on 2020/09/21 11:54:00 UTC

[jira] [Resolved] (CALCITE-4241) Some improvements to metadata query

     [ https://issues.apache.org/jira/browse/CALCITE-4241?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Liya Fan resolved CALCITE-4241.
-------------------------------
    Resolution: Fixed

> 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: 1h 50m
>  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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