Re: WIP: explain analyze with 'rows' but not timing
Pavel Stehule <pavel.stehule@gmail.com>
From: Pavel Stehule <pavel.stehule@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Tomas Vondra <tv@fuzzy.cz>, pgsql-hackers@postgresql.org
Date: 2011-12-24T05:31:31Z
Lists: pgsql-hackers
2011/12/23 Tom Lane <tgl@sss.pgh.pa.us>: > Pavel Stehule <pavel.stehule@gmail.com> writes: >> 2011/12/23 Tom Lane <tgl@sss.pgh.pa.us>: >>> Tomas Vondra <tv@fuzzy.cz> writes: >>>> The motivation for this patch was that collection timing data often >>>> causes performance issues and in some cases it's not needed. But is this >>>> true for row counts? > >>> Perhaps more to the point, is there a use case for collecting timing >>> data without row counts? I find it hard to visualize a valid reason. > >> yes - a searching of bad prediction > > No, because timing alone proves nothing at all. The machine could just > have been overloaded. sorry, I didn't understand to question. Using only time is not practical Regards Pavel > > regards, tom lane