On Mon, 2010-06-07 at 20:10 +0100, Martin Simmons wrote: > >>>>> On Mon, 7 Jun 2010 18:24:34 +0200, Florian Heigl said: > > > > Hi all, > > > > > Within psql/mysql: > > > 1) select count(*) from File; 1sec 30min > > > > Disclaimer: I don't know a dime's worth of databases per se. But I > > spend a lot of time hunting other peoples performance issues. :) > > > > I think you should start identifying the cause for this bit at the > > very first, as it shows the absolutely worst perfomance and probably > > what slows this also slows the rest. > > My nose says this is really smelly and should'nt even take as long > > without any indexes. > > Is counting all rows ever fast on postgres? For me, it runs a sequential > scan, which is always slow. It is probably never done with millions of rows > in a real application, so noone has optimized it. >
It runs a sequential scan because of MVCC. Please see http://wiki.postgresql.org/wiki/Slow_Counting I don't know MySQL very well, but I imagine that a count(*) on an InnoDB database should be as slow > __Martin > > ------------------------------------------------------------------------------ > ThinkGeek and WIRED's GeekDad team up for the Ultimate > GeekDad Father's Day Giveaway. ONE MASSIVE PRIZE to the > lucky parental unit. See the prize list and enter to win: > http://p.sf.net/sfu/thinkgeek-promo > _______________________________________________ > Bacula-users mailing list > Bacula-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bacula-users ------------------------------------------------------------------------------ ThinkGeek and WIRED's GeekDad team up for the Ultimate GeekDad Father's Day Giveaway. ONE MASSIVE PRIZE to the lucky parental unit. See the prize list and enter to win: http://p.sf.net/sfu/thinkgeek-promo _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
