Mark Rae wrote: > On Tue, Mar 15, 2005 at 12:51:03PM -0800, Jeff Davis wrote: > > Be careful assuming that. DB benchmarks are hard to do in a general > > sense. His results probably indicate a general trend, but you should > > test your application yourself to get a real result. His pattern of SQL > > queries might be very different from yours. > > Very true. > > You may have noticed that I had a very low query rate of 5.8 queries > per second, because some of the queries have 12 tables to join and > take about 20s to run. This tends to work in postgres' favour. > If you have lots have simple queries, it will be better for mysql > and the break even point will be higher. > > > Also, while on the subject of scaling. I had the opportunity > to try postgres on a 16CPU Altix and couldn't get it to scale > more than about 4x, whereas Oracle got up to about 12x faster > > I assume this is because of the NUMA architecture. I was also > told that Oracle had made no special optimizations to accomodate it. > > My guess is that because postgres allocates all its shared > buffers as a contiguous chunk, it puts all the load on one > memory bank. > Oracle on the other hand, seems to use lots of smaller regions > which would probably be spread throughout the physical memory. > > Perhaps one of the developers could comment on how difficult > it would be to change the shared buffer handling to use multiple > segments. As I'd definitely be willing to give it a go.
We have had some major SMP improvements in current CVS. Were you testing that or 8.0.X? -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073 ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org
