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From "C.S. Nirmal J. Fernando (JIRA)" <j...@apache.org>
Subject [jira] Commented: (DERBY-4587) Add tools for improved analysis and understanding of query plans and execution statistics
Date Wed, 21 Apr 2010 13:31:53 GMT

    [ https://issues.apache.org/jira/browse/DERBY-4587?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12859351#action_12859351
] 

C.S. Nirmal J. Fernando commented on DERBY-4587:
------------------------------------------------

Thanks Knut. That gave me the expected result. But I wonder why it left blank space between
the value and the closing tag (This won't be an affect in this case, just curious though).

Thanks Bryan for the reply but we cannot convert numeric type to varchar. Any way Knut's suggestion
worked fine so we can use ,

SELECT '<result_set>'|| 
              '<type>'|| CHAR (op_identifier) ||'</type>'|| 
              '<no_opens>'||CHAR(no_opens)||'</no_opens>'|| 
              ... repeat for the other columsn from sysxplain_resultsets... 
              '</result_set>' 
   FROM xxx.sysxplain_resultsets WHERE ... 
                                                                                     this
way to produce small XML fragments, and then stitch them to an .xml file. (of course we need
to add XML related lines up front)

  

> Add tools for improved analysis and understanding of query plans and execution statistics
> -----------------------------------------------------------------------------------------
>
>                 Key: DERBY-4587
>                 URL: https://issues.apache.org/jira/browse/DERBY-4587
>             Project: Derby
>          Issue Type: Improvement
>          Components: SQL, Tools
>            Reporter: Bryan Pendleton
>            Assignee: Bryan Pendleton
>         Attachments: Derby Query Plan Screen Shot 2.jpg, Derby_Query_Plan_Screen_Shot.jpg,
PostgreSQL license.jpg, Read_Me.txt, Source.rar
>
>
> I think it would be great to see some work in the area of tools for helping
> with the analysis of complex query execution. Quite frequently, users of
> Derby have trouble comprehending (a) how their query is being translated
> into a query plan by the optimizer, and (b) what the execution-time resource
> usage of the various parts of the query is.
> There are low-level features in Derby which capture this information and
> record it, such as logQueryPlan, and the XPLAIN tables, but there is a lot
> of opportunity for designing higher-level tools which can process the query
> plan and execution statistics information and present it in a more
> comprehensible fashion. 

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