Sai Sadashiva Kundurmutt <saisadashiva2000@gmail.com> writes: > I wanted to know whether the numbers calculated by ANALYZE for number of > pages are exact(the relpages field in pg_class).
If memory serves, relpages is accurate as of the time of the last VACUUM or ANALYZE on the table, but of course it could be arbitrarily out of date later.
> I had the impression that > it is exact because during random sampling the number of pages is assumed > to be known.
What makes you think that? And even more to the point, what makes you think that we'd rely on relpages for such a purpose? I'd expect a fresh RelationGetNumberOfBlocks call in any scan that had a need to know the table size.
