Re: count * performance issue

>
> There aren't a general solution. If you realy need the exact count of
> tuples than you can play with a TRIGGER and increase/decrease the
> tuple-count for this table in an extra table.
>

Of course, this means accepting the cost of obtaining update locks on
the count table.

The original poster should understand that they can either get a fast
estimated count, or they can get a slow accurate count (either slow in
terms of select using count(*) or slow in terms of updates using
triggers and locking).

Other systems have their own issues. An index scan may be faster than a
table scan for databases that can accurately determine counts using only
the index, but it's still a relatively slow operation, and people don't
normally need an accurate count for records in the range of 100,000+? :-)

Cheers,
mark

--
Mark Mielke <mark(at)mielke(dot)cc>