Re: BUG #4462: Adding COUNT to query causes massive slowdown - Mailing list pgsql-bugs

Jussi Pakkanen wrote:
> However when I try to count the amount of distinct codes, I get this:
>
>
> EXPLAIN SELECT COUNT(DISTINCT code) FROM log;
>                                    QUERY PLAN
> ----------------------------------------------------------------------------
> -----
>  Aggregate  (cost=100801488.30..100801488.31 rows=1 width=10)
>    ->  Seq Scan on log  (cost=100000000.00..100721245.24 rows=32097224
> width=10)
> (2 rows)

This looks like you have one of the enable_${plantype} parameters turned
off.  100000000 is the penalty that is added when a plantype if turned off.