On Mon, Oct 27, 2003 at 12:52:27PM +0530, Shridhar Daithankar wrote: > Dror Matalon wrote: > > >On Mon, Oct 27, 2003 at 01:04:49AM -0500, Christopher Browne wrote: > >>Most of the time involves: > >> > >>a) Reading each page of the table, and > >>b) Figuring out which records on those pages are still "live." > > > > > >The table has been VACUUM ANALYZED so that there are no "dead" records. > >It's still not clear why select count() would be slower than select with > >a "where" clause. > > Do a vacuum verbose full and then everything should be within small range > of each other. >
I did vaccum full verbose and the results are the same as before, 55 seconds for count(*) and 26 seconds for count(*) where channel < 5000. > Also in the where clause, does explicitly typecasting helps? > > Like 'where channel<5000::int2;' It makes no difference. > > HTH > > Shridhar > -- Dror Matalon Zapatec Inc 1700 MLK Way Berkeley, CA 94709 http://www.zapatec.com ---------------------------(end of broadcast)--------------------------- TIP 7: don't forget to increase your free space map settings
