Geo Carncross wrote: > On Thu, 2005-12-15 at 17:35 +0100, Thomas Mueller wrote: > > Geo Carncross wrote: > > > > > I completely agree with this. There's just the problem of databases > > > being a moving target. Remember we talked about COUNT(*) not being > > > optimally implemented in Pg, but one day it could be, and at that point, > > > we should use COUNT(*) - even if it's slower on older database versions. > > > > That day is in the past :-) 8.1 release notes: > > > > Faster Aggregates: aggregate functions have been improved to make > > reporting queries even faster. The PostgreSQL developers both rewritten > > memory management for aggregates and added indexing optimizations for > > MIN() and MAX(). > > Woot! > > I mean, does it apply specifically to COUNT(*)? I checked the release > notes and I couldn't find mention of it...
If you're looking to find the total size of a table, no. In PostgreSQL, that's a Fundamentally Hard Problem because of MVCC. It will make use of indexes in the WHERE clause, of course, to limit the rows it has to visit. I think that's always been the case. -- Kevin Brown [EMAIL PROTECTED]
