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From David Van Couvering <David.Vancouver...@Sun.COM>
Subject Re: Feedback for extension
Date Wed, 19 Jul 2006 17:48:09 GMT
Hi, Felix, this sounds like very interesting work!  My only question at 
this stage would be, are these new features standards-based?  There may 
be some resistance to adding interfaces that are not based on a 
standard, as that is one of the guiding principles of the Derby project. 
  Although if it's used mostly for performance analysis and is not part 
of the interfaces used by applications, the resistance may be less 
strong.   Anybody else have thoughts on this?

Are you planning to contribute your query plan visualization tool as 
well?  It sure sounds useful to me (although we'd need to understand 
what license the JGraph framework is under and whether it's compatible 
with the Apache license).


Felix Beyer wrote:
> Hello Derby Community,
> my name is Felix Beyer and I´m a student at the Dresden University of 
> Technology. I´m right before writing my diploma thesis, which inculdes 
> an extension of Derby. Please give me some feedback to let me know if I 
> should merge my extensions into a current code branch of Derby.
> The core of my topic consists of two major tasks:
> First, I want to extend Derby with Explain Table functionality. That 
> means I want to develop a mechanism to store the generated query plans 
> in appropriate system tables. In order to do this I will have to examine 
> current system functions like GetRuntimeStatistics() and the overall 
> process from parsing to execution of a statement. Further investigations 
> have to be made to develeop solutions for questions like: Which 
> information is additionally available and could be aggregated or 
> derived? Which modifications are necessary to extract this information? 
> How big is the performance impact during the rising of explain table 
> information?
> The second big task will be to extend Derby to store Workload 
> information. Investigations have to be made on reasonable aggregation 
> and mandatory reduction of workload, general scheme of workload 
> information, support for application domains using this workload 
> information, comparison to other DBMS etc.
> Now, the following question arises: What does the Derby community think 
> of such extensions? Please give me some feedback. The feedback you 
> provide will be the basis of the decision if my extensions should be 
> merged into a current code branch of Derby or will be integrated into 
> our code branch.
> By the way, in a former project I managed to extend Derby to extract the 
> generated optimized query plans in form of XML files for visualizing 
> them in an external application. I used the GXL file format for export 
> and visualized the plans with the JGraph Framework. Internal changes 
> affected the current Derby structure in two ways: First of all a new 
> system function was added to toggle query extraction on or off and 
> second a visitor pattern was used to collect the required information 
> through a traverse of the query tree after the optimization step.
> Greetings,
> Felix Beyer

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