旭斌 裴 escreveu:
> The postgresql database uses the table full scan.but in oracle, the
> similar SQL uses the index full scanning,speed quickly many than
> postgresql.
>
This was discussed many times on the pgsql mailing lists. Search the archives.
Also, take a look at [1].
[1] http://wiki.postgresql.org/wiki/Slow_Counting
--
Euler Taveira de Oliveira
http://www.timbira.com/