On Fri, Nov 4, 2011 at 4:10 PM, Robert Haas <robertmh...@gmail.com> wrote: > On Tue, Nov 1, 2011 at 8:07 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: >> It's the "lobotomized engines" that are the problem, IMO --- people >> coming from databases like mysql tend to think count(*) just means >> reading a table size counter that the engine has anyway. > > This is probably a much less common misconception than formerly, due > to the rise of InnoDB and the falling-out-of-favor experienced by > MyISAM. > > I think some pessimism removal is probably warranted. Yeah, somebody > else might be faster than us on this test, but that's probably true of > many tests. And on others we will be faster than them.
So, if Tom still wants to keep that paragraph and its warning, how about we just fix the now-incorrect bit at the end? Maybe just tweak "will be executed" to "will often be executed", or change "using a sequential scan of the entire table." to "using a sequential scan of the table, or an index-only scan of one of its indexes". Josh -- Sent via pgsql-docs mailing list (pgsql-docs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-docs
