Re: add_path optimization - Mailing list pgsql-hackers

From Kevin Grittner
Subject Re: add_path optimization
Date
Msg-id 498804B6.EE98.0025.0@wicourts.gov
Whole thread Raw
In response to Re: add_path optimization  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-hackers
>>> Robert Haas <robertmhaas@gmail.com> wrote: 
> FYI, I retested my queries on REL8_3_STABLE and the results were not
> all that different from CVS HEAD.  So the problem is apparently
> specific to something your query is doing that mine isn't., rather
> than a general slowdown in planning (or else one of us goofed up the
> testing).
I know you said size doesn't matter, but just for the record, the ten
tables I loaded for this test put the database at 56G.  I'm pulling
information together to share on this, but I was wondering: is there
any possibility that the tendency to use index scans in nested loops
(given the table sizes and the availability of useful indexes)
contributes to the difference?
Other possible factors:
Most keys are multi-column and include varchar-based data types.
Most columns are defined via domains.
(More info to follow.)
-Kevin


pgsql-hackers by date:

Previous
From: Magnus Hagander
Date:
Subject: Re: pgevent warnings on mingw
Next
From: Andres Freund
Date:
Subject: Re: Hot Standby (v9d)