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From Ян Программист <webautoma...@gmail.com>
Subject Re: [jira] Commented: (DERBY-4587) Add tools for improved analysis and understanding of query plans and execution statistics
Date Sun, 18 Apr 2010 10:58:00 GMT
http://www.castor.org/xml-framework.html to the rescue!

2010/4/18 C.S. Nirmal J. Fernando (JIRA) <jira@apache.org>:
>    [
> C.S. Nirmal J. Fernando commented on DERBY-4587:
> ------------------------------------------------
> Hi Bryan,
> I had a look on using XML operations in Derby more thoroughly and found
out following important points:
> * In order to retrieve XML data using XMLSERIALIZE, we should first have a
table column which is in XML data type.
>         So is it possible to change SYSXPLAIN tables such that they store
XML data of each row inserted, in a XML data type column?
> * When inserting XML data we have to insert some set of XML keywords, such
as Document, Preserve Whitespace.
>         eg: insert into t(a) values (XMLPARSE(DOCUMENT
'<title>Derby</title>' PRESERVE WHITESPACE));
> * When using XMLSERIALIZE we should use 'as' sql key word,
>        eg: select XMLSERIALIZE(a as CLOB) from t;   //we can use varchar
as well
> * Execution of XMLSERIALIZE statement will result a small XML fragment.
>        eg: <title>Derby</title>
> I think this will be an easy way, if we can somehow add a XML data type
columns to SYSXPLAIN tables.
> May be we can store these small xml fragments in another table with XML
data type columns and retrieve the large XML document after the execution of
the query. (Note: We may have to write those rows retrieved into a .xml
> Thanks.
>> 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,
>> I think it would be great to see some work in the area of tools for
>> 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
>> 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
>> of opportunity for designing higher-level tools which can process the
>> plan and execution statistics information and present it in a more
>> comprehensible fashion.
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