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From Rick Hillegas <rick.hille...@gmail.com>
Subject Re: help understanding the query optimizer
Date Mon, 16 Mar 2015 00:27:43 GMT
On 3/13/15 7:19 PM, Federico Bertola wrote:
> Hi,
>
> I'm trying to understand the query optimizer for research purpose. As 
> the codebase is quite huge, I would like some advice, i.e. where to 
> look and what tests should I inspect.
> What I really trying to do is to isolate the query optimizer so that I 
> could get and show a plan without the need to execute the query with a 
> full db stack. Of course this would require some wrapping but I think 
> it is doable.
>
> Thanks a lot for your help!
>
> Best regards,
> Federico.
>
Hi Federico,

Information on printing out query plans can be found in the "Working 
with RunTimeStatistics" section of the Derby Tuning Guide: 
http://db.apache.org/derby/docs/10.11/tuning/ctundepth13055.html

Information on tracing the optimizer's processing can be found here: 
http://wiki.apache.org/db-derby/OptimizerTracing

Information on how to turn off Derby processing at the end of the 
optimization phase (on a debug Derby engine) can be found here: 
http://wiki.apache.org/db-derby/DebugPropertiesTmpl

Hope this helps,
-Rick

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