[jira] [Updated] (CALCITE-4522) Sort compute the io cost even if the RelCollation is empty

["hqx (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CALCITE-4522?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

hqx updated CALCITE-4522:
-------------------------
    Summary: Sort compute the io cost even if the RelCollation is empty  (was: Sort#computeSelfCost doesn't consider the RelCollation is empty)

> Sort compute the io cost even if the RelCollation is empty
> ----------------------------------------------------------
>
>                 Key: CALCITE-4522
>                 URL: https://issues.apache.org/jira/browse/CALCITE-4522
>             Project: Calcite
>          Issue Type: Improvement
>          Components: core
>            Reporter: hqx
>            Priority: Minor
>
> The old method to compute the cost of sort has some problem.
>  # when there is no need to sort, it still to compute the cpu cost of sort.
>  # use n * log\(n) * rowBytes to estimate the cpu cost may be inaccurate, where n means the output row count of the sort operator, and rowBytes means the average bytes of one row .
> Instead, I give follow suggestion.
>  # the cpu cost is zero if there is no need to sort.
>  # use m * log\(n)* rowBytes to compute the cpu cost, where m is the sum of offset + limit and n means input row count.



--
This message was sent by Atlassian Jira
(v8.3.4#803005)