Re: Planner estimates cost of 'like' a lot lower than '='??

Buddy Lee Haystack <haystack@email.rentzone.org>

From: Buddy Lee Haystack <haystack@email.rentzone.org>
To: Mats Lofkvist <mal@algonet.se>
Cc: pgsql-general@postgresql.org
Date: 2001-07-22T13:50:30Z
Lists: pgsql-general
Mats Lofkvist wrote:
> 
> I have a multiple-join select that takes ~70 seconds to execute
> but if I remove one of the indexes the time drops to ~2 seconds.
> 
>       _
> Mats Lofkvist
> mal@algonet.se
> 

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.