Re: Make COUNT(*) Faster?

In article <758d5e7f05070808305c049aae(at)mail(dot)gmail(dot)com>,
Dawid Kuroczko <qnex42(at)gmail(dot)com> writes:

> Use
> EXPLAIN SELECT * FROM yourcountedtable;

> Planner seems to track estimated statistics on-the-fly. :)

> You can even wrap EXPLAIN SELECT in a pgsql function if you
> need it.

Do you know how to do that? A function "approx_count(tablename)"
would be really handy, but

FOR row IN EXECUTE 'EXPLAIN SELECT * FROM ' || tbl LOOP

fails with the following message:

ERROR: cannot open non-SELECT query as cursor

> PS: And be aware that these are 'statistics'. And the statement that there
> are lies, big lies and statistics is sometimes true even for PostgreSQL. ;-)

Does this mean that PostgreSQL believes only in statistics it has
faked itself? ;-)