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Posted to issues@calcite.apache.org by "Haisheng Yuan (Jira)" <ji...@apache.org> on 2020/04/23 04:09:00 UTC
[jira] [Commented] (CALCITE-3952) Improve SortRemoveRule to remove
Sort based on rowcount
[ https://issues.apache.org/jira/browse/CALCITE-3952?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17090212#comment-17090212 ]
Haisheng Yuan commented on CALCITE-3952:
----------------------------------------
What if we have limit 0?
> Improve SortRemoveRule to remove Sort based on rowcount
> -------------------------------------------------------
>
> Key: CALCITE-3952
> URL: https://issues.apache.org/jira/browse/CALCITE-3952
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Reporter: Vineet Garg
> Assignee: Vineet Garg
> Priority: Major
>
> If a query is guaranteed to produce maximum one row it is safe to remove Sort (along with limit).
> Example:
> {code:sql}
> select count(*) cs from store_sales where ss_ext_sales_price > 100.00 order by cs limit 100
> {code}
> Although logically equivalent this can greatly benefit physical plans by removing extra operator and avoiding unnecessary data transfer.
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