Re: Select count(*) in Oracle and MySQL

On Sep 19, 2:40 pm, Occidental <Occiden..._at_comcast.net> wrote:
> I have a table with about 250M rows, implemented in both Oracle and
> MySQL.
> Select count(*) in MySQL is effectively instantaneous, presumably
> because it accesses some internal count that is maintained by the
> DBMS. The same query in Oracle takes about 6 minutes, pretty obviously
> becasue it counts rows. The Oracle table should have been set up with
> a primary key, but wasn't. The MySQL table has no primary key either.
> Any comments?

Oracle recommends using count(rowid) instead of count(*) for performance reasons, I think you'll find this much faster.

http://www.thewellroundedgeek.com/2007/09/most-people-use-oracle-count-function.html

• Rich