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
