Re: Select count(*) in Oracle and MySQL

On Oct 9, 9:41 am, "richard.drouill..._at_gmail.com" <richard.drouill..._at_gmail.com> wrote:
> 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-coun...
>
> - Rich

I see this 'recommendation' on your blog, but I don't see any reference to Oracle Corp. making this claim.

David Fitzjarrell Received on Tue Oct 09 2007 - 10:19:25 CDT