Horton

gincostestimate

Teodor Sigaev <teodor@sigaev.ru>

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From: Teodor Sigaev <teodor@sigaev.ru>
To: Pgsql Hackers <pgsql-hackers@postgresql.org>
Date: 2010-07-02T12:33:31Z
Lists: pgsql-hackers

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Patch implements much more accuracy estimation of cost for GIN index scan than 
generic cost estimation function. Basic idea is described on PGCon-2010: 
http://www.sai.msu.su/~megera/postgres/talks/pgcon-2010-1.pdf, pages 48-54.

After discussion on PGCon, the storage of additional statistic information has 
been changed from pg_class table to meta-page of index. Statistics data is 
cached in Relation->rd_amcache to prevent frequent read of meta-page.

-- 
Teodor Sigaev                                   E-mail: teodor@sigaev.ru
                                                    WWW: http://www.sigaev.ru/