Skip site navigation (1) Skip section navigation (2)

Re: Planner selects slow "Bitmap Heap Scan" when "Index Scan" is faster

From: "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>
To: <pgsql-performance(at)postgresql(dot)org>,"Kim Hansen" <kim(at)rthansen(dot)dk>
Subject: Re: Planner selects slow "Bitmap Heap Scan" when "Index Scan" is faster
Date: 2012-04-05 15:34:36
Message-ID: 4F7D753C0200002500046BF5@gw.wicourts.gov (view raw or flat)
Thread:
Lists: pgsql-performance
Kim Hansen <kim(at)rthansen(dot)dk> wrote:
 
> I have a query where the planner makes a wrong cost estimate, it
> looks like it underestimates the cost of a "Bitmap Heap Scan"
> compared to an "Index Scan".
 
> What can I do to fix the cost estimate?
 
Could you try running the query with cpu_tuple_cost = 0.05 and let
us know how that goes?
 
-Kevin

In response to

Responses

pgsql-performance by date

Next:From: Gregg JaskiewiczDate: 2012-04-05 15:39:26
Subject: heavly load system spec
Previous:From: Kevin GrittnerDate: 2012-04-05 15:01:25
Subject: Re: about multiprocessingmassdata

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group