On Thu, 2 Oct 2003, Christopher Browne wrote:
> I can't imagine why the raw number of tuples in a relation would be
> expected to necessarily be terribly useful.
>
We use stuff like that for reporting queries.
example:
On our message boards each post is a row. The powers that be like to know
how many posts there are total (In addition to 'today')-
select count(*) from posts is how it has been
done on our informix db. With our port to PG I instead select reltuples
pg_class.
I know when I login to a new db (or unknown to me db) the first thing I do
is look at tables and see what sort of data there is.. but in code I'd
rarely do that.
I know some monitoring things around here also do a select count(*) on
sometable to ensure it is growing, but like you said, this is easily done
with the number of pages as well.
yes. Informix caches this data. I believe Oracle does too.
Mysql with InnoDB does the same thing PG does. (MyISAM caches it)
--
Jeff Trout <jeff@jefftrout.com>
http://www.jefftrout.com/
http://www.stuarthamm.net/