[jira] [Commented] (DERBY-6938) Obtain cardinality estimates and true estimates for base tables as well as for intermediate results for queries involving multiple joins.

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[jira] [Commented] (DERBY-6938) Obtain cardinality estimates and true estimates for base tables as well as for intermediate results for queries involving multiple joins.

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    [ https://issues.apache.org/jira/browse/DERBY-6938?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16110605#comment-16110605 ]

Harshvardhan Gupta commented on DERBY-6938:
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Bryan,

I agree with your observations. For production of efficient query plans, Cardinality Estimates, Cost estimation and Plan space are all inter dependent on each other. I am filing another issue under DERBY-6949 to track the effort on modelling HASH join's spill behaviour. I will also update cost modelling details under DERBY-6949 shortly after I had to take a detour analyzing HASH Join's behaviour.

Thanks,
Vardhan

>  Obtain cardinality estimates and true estimates for base tables as well as for intermediate results for queries involving multiple joins.
> -------------------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: DERBY-6938
>                 URL: https://issues.apache.org/jira/browse/DERBY-6938
>             Project: Derby
>          Issue Type: Sub-task
>          Components: SQL
>            Reporter: Harshvardhan Gupta
>            Assignee: Harshvardhan Gupta
>         Attachments: explain.txt, traceout.txt
>
>




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