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From "Bryan Pendleton (JIRA)" <j...@apache.org>
Subject [jira] Commented: (DERBY-2487) Enhance Derby with EXPLAIN Functionality
Date Fri, 27 Feb 2009 23:21:13 GMT

    [ https://issues.apache.org/jira/browse/DERBY-2487?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12677599#action_12677599
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Bryan Pendleton commented on DERBY-2487:
----------------------------------------

I suspect that the 'sourceDepth' column should be removed from SYSXPLAIN_RESULTSETS.
If I'm reading the source code correctly, this field is used during the text formatting
of the runtime statistics information to manage the indentation levels of the text display;
it is incremented by one in the initFormatInfo() method when a parent resultset
constructs its own text by calling upon its child result sets to produce their text.
I don't think that it has any value when the runtime statistics information is captured
into the SYSXPLAIN_RESULTSETS table.

I intend to remove the sourceDepth field from the code patch, and from the docs patch.


> Enhance Derby with EXPLAIN Functionality
> ----------------------------------------
>
>                 Key: DERBY-2487
>                 URL: https://issues.apache.org/jira/browse/DERBY-2487
>             Project: Derby
>          Issue Type: New Feature
>          Components: SQL
>    Affects Versions: 10.2.2.0
>            Reporter: Felix Beyer
>            Assignee: Bryan Pendleton
>            Priority: Minor
>         Attachments: Derby physical XPLAIN schema.png, incorporateTrunkChanges.diff,
RSProtocolNew.pdf, rts.xls, small logical xplain schema.pdf, startRegressionTest.diff, startRegressionTest.diff,
startUpgradeTests.diff, updateRegressionTests.diff, updateRegressionTests.diff, usage.txt,
xplain_patch_v1.txt, xplainClasses.pdf
>
>
> This enhancement extends Derby with EXPLAIN functions. Users want to have more feedback
than they`re getting with the current RuntimeStatistics facility. This extension is based
on the RuntimeStatistics/ResultSetStatistics functions / classes. 

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