Re: On query rewrite - Mailing list pgsql-hackers

From Sailesh Krishnamurthy
Subject Re: On query rewrite
Date
Msg-id mjqfz9kk1h7.fsf@cs.berkeley.edu
Whole thread Raw
In response to Re: On query rewrite  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: On query rewrite  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
>>>>> "Tom" == Tom Lane <tgl@sss.pgh.pa.us> writes:
   Tom> This particular issue is handled as part of our Path   Tom> enumeration mechanism, but the more hard-wired
sortsof   Tom> transformations that you are asking about live mostly in
 

Thanks again. To confirm the actual cost comparison with plan
enumeration is a dynamic programming algorithm, is it not ?
Selinger-style with 2-way join paths enumerated, then 3-way using the
best 2-way etc. ? 

BTW, do lots of people use the GEQO ? 
   Tom> optimizer/prep/* and plan/planner.c.  In particular you   Tom> probably want to look at prepjointree.c and
prepqual.c.  Tom> (Note prepqual also looks considerably different in CVS tip   Tom> than in prior releases.)
 

Thanks .. I've extracted cvstip .. sigh .. one of these days I'll have
to do another merge with the TelegraphCQ code. You guys hack too much :-)

-- 
Pip-pip
Sailesh
http://www.cs.berkeley.edu/~sailesh




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