Re: Make COUNT(*) Faster?

Steve Wampler <swampler@noao.edu> writes:
> Tom Lane wrote:
>> If you want something cheap, you could use the same technique the
>> planner uses nowadays: take RelationGetNumberOfBlocks() (which is
>> guaranteed accurate) and multiply by reltuples/relpages.

> Yes - this would be an excellent approximation for my needs!  The
> solution that Dawid Kuroczko suggested (just call "explain select *
> on ..." and parse the result) would be equivalent these days, right?

Close enough (the planner actually does some additional heuristic
stuff to avoid going crazy on corner cases).
        regards, tom lane