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From "Knut Anders Hatlen (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 08:22:49 GMT

    [ https://issues.apache.org/jira/browse/DERBY-4587?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12859255#action_12859255
] 

Knut Anders Hatlen commented on DERBY-4587:
-------------------------------------------

I don't think you can cast a numeric type to a character type. But there is a CHAR function
(http://db.apache.org/derby/docs/10.5/ref/rrefbuiltchar.html) that converts various data types
to CHAR.

So for example: ... || '<no_opens>' || CHAR(no_opens) || '</no_opens>' || ...

> 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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