Re: BUG #1408: don't see index - Mailing list pgsql-bugs

On Tue, Jan 18, 2005 at 09:01:29 +0000,
  andrzej <wppl16@wp.pl> wrote:
>
> The following bug has been logged online:
>
> Bug reference:      1408
> Logged by:          andrzej
> Email address:      wppl16@wp.pl
> PostgreSQL version: 8.0.0-rc5
> Operating system:   windows XP
> Description:        don't see index
> Details:
>
> Create table t1
> (
>  v varchar(5) not null,
>  m varchar(20),
>  d date,
>  l varchar(10),
>  primary key(v)
> );
>
> explain select * from t1 where v='abc'
> result:
> Seq Scan on t1 (....
> Filter:((v)::text='abc'::text)
> DON'T SEE INDEX PKEY ???????!!!!
>
> but Postgres 7.4.2 Linux
> explain select * from t1 where v='abc'
> result:
> Index Scan using t1_pkey on t1(...
> Index Cond((v)::text='abc'::text)
> SEE INDEX PKEY OK !!!!!

This probably isn't a bug. In some circumstances a sequential scan is faster
than an index scan.

How many rows are in this table?
Have you run an ANALYZE on the table?