[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=16097272#comment-16097272 ]

Harshvardhan Gupta commented on DERBY-6938:
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Summarizing  my analysis of HASH based joins so far -

Derby has the capability to perform HASH Joins spilling to disk but has long ignored them due to the absence of a cost model around such a behaviour. DERBY-1259 also talks about the history of HASH Joins and the changes made as part of DERBY-106.

>  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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