Re: Planner estimates cost of 'like' a lot lower than '='?? - Mailing list pgsql-general

From Mats Lofkvist
Subject Re: Planner estimates cost of 'like' a lot lower than '='??
Date
Msg-id y2q66clrpvf.fsf@algonet.se
Whole thread Raw
In response to Re: Planner estimates cost of 'like' a lot lower than '='??  (Buddy Lee Haystack <haystack@email.rentzone.org>)
List pgsql-general
haystack@email.rentzone.org (Buddy Lee Haystack) writes:

> I ran into a similar problem on RedHat Linux v6.1 on Intel, kernel
> 2.2.12-20, PostgreSQL 6.5.3 when moving a system from a single processor
> development box over to a dual processor production server. Dropping one
> of the indexes on a lookup table with roughly 68,000 records on the
> production box resulted in roughly a 3 fold increase in query execution
> speed. At the time, I thought it was an SMP issue, and have since been
> extremely conservative in adding indexes on SMP boxes.

I _am_ running it on an SMP box (FreeBSD 5.0-current from january
this year), but isn't it a bit far-fetched to assume that this is
an SMP issue? Is postgres even aware of running on an SMP box?
(if it isn't, why should the planner estimates differ depending
on if it is running on an SMP box or not?)

Forgive me for sounding negative, but I fail to see the connection.
Am I missing something?

      _
Mats Lofkvist
mal@algonet.se

pgsql-general by date:

Previous
From: Bruno Wolff III
Date:
Subject: Re: How Postgresql Compares... Count(*) and others
Next
From: Tom Lane
Date:
Subject: Re: VACUUM ANALYZE