Re: Slow SELECT with distinct, in a TIMESTAMP type column

On 24 Jun 2002, Marcos Garcia wrote:

> The problem is that my query is too slow when i use distinct:
>
> pgsql> explain analyze SELECT distinct(smsdate) FROM send_total;
>
> NOTICE:  QUERY PLAN:
>
> Unique  (cost=15840.31..15870.81 rows=1220 width=8) (actual
> time=56358.93..56452.78 rows=6670 loops=1)
>   ->  Sort  (cost=15840.31..15840.31 rows=12203 width=8) (actual
> time=56358.91..56436.95 rows=12062 loops=1)
>         ->  Seq Scan on send_total  (cost=0.00..15012.03 rows=12203
> width=8) (actual time=0.55..56205.25 rows=12062 loops=1)
> Total runtime: 56518.26 msec

As a question, what does explain analyze show if you
set enable_seqscan=off; first?