Re: Sub-optimal plan chosen

From: tv(at)fuzzy(dot)cz
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: Sub-optimal plan chosen
Date: 2009-09-10 15:40:24
Message-ID: 52984.193.179.187.70.1252597224.squirrel@sq.gransy.com
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> Playing around with seq_page_cost (1) and random_page_cost (1), I can get
> the correct index selected. Applying those same settings to our production
> server does not produce the optimal plan, though.

I doubt setting seq_page_cost and random_page_cost to the same value is
reasonable - random access is almost always more expensive than sequential
access.

Anyway, post the EXPLAIN ANALYZE output from the production server. Don't
forget there are other _cost values - try to modify them too, but I'm not
sure how these values relate to the bitmap heap scan / bitmap index plans.

regards
Tomas

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