Ismail Kizir wrote:
> Hi everybody,
> 1 .... EXPLAIN SELECT COUNT(*) AS c FROM articletbl WHERE
> ((mydate BETWEEN '2004-04-24' AND '2004-05-24' )
> 2 .... EXPLAIN SELECT COUNT(*) AS c FROM articletbl WHERE
> ((mydate = '2004-04-24')
> (I ran VACUUM ANALYZE before running those)
> mydate is an indexed date column.
> The optimizer optimizes the second query but, it doesn't optimize the first
> one and decides to make a "sequential scan".
> Is this a bug?
> Or may someone explain me the reason?
> Thanks in advance.
> Ismail Kizir
If 2004-04-24 to 2004-05-24 make up let's say 90% of your data
PostgreSQL will find out that it is cheaper to use a seq scan instead of
This is not a bug at all - this is normal and desired behaviour ...
Cybertec Geschwinde u Schoenig
Schoengrabern 134, A-2020 Hollabrunn, Austria
Tel: +43/720/10 1234567 or +43/664/233 90 75
www.cybertec.at, www.postgresql.at, kernel.cybertec.at
In response to
pgsql-hackers by date
|Next:||From: Ismail Kizir||Date: 2004-05-24 17:27:01|
|Subject: Re: Optimizer bug??|
|Previous:||From: Ismail Kizir||Date: 2004-05-24 16:38:58|
|Subject: Optimizer bug??|