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From Felix Beyer <s4224...@mail.inf.tu-dresden.de>
Subject Feedback for extension
Date Wed, 19 Jul 2006 15:57:15 GMT
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 

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.

Felix Beyer

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