Aaron, > I do consulting, so they're all over the place and tend to be complex. Very > few fit in RAM, but still are very buffered. These are almost all backed > with very high end I/O subsystems, with dozens of spindles with battery > backed up writethrough cache and gigs of buffers, which may be why I worry > so much about CPU. I have had this issue with multiple servers.
Aha, I think this is the difference. I never seem to be able to get my clients to fork out for adequate disk support. They are always running off single or double SCSI RAID in the host server; not the sort of setup you have. > What my CPU tends to be doing is a combination of general processing, > complex SQL processing: nested loops and sorting and hashing and triggers > and SPs. I haven't noticed SPs to be particularly CPU-hoggish, more RAM. > I'm curious about you having flat CPU, which is not my experience. Are your > apps mature and stable? Well, "flat" was a bit of an exaggeration ... there are spikes ... but average CPU load is < 30%. I think the difference is that your clients listen to you about disk access. Mine are all too liable to purchase a quad-Xeon machine but with an Adaptec RAID-5 card with 4 drives, and *then* call me and ask for advice. As a result, most intensive operations don't tend to swamp the CPU because they are waiting for disk. I have noticed the limitiations on RAM for 64 vs. 32, as I find it easier to convince a client to get 8GB RAM than four-channel RAID with 12 drives, mostly because the former is cheaper. Linux 2.4 + Bigmem just doesn't cut it for making effective use of > 3GB of RAM. -- Josh Berkus Aglio Database Solutions San Francisco ---------------------------(end of broadcast)--------------------------- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faqs/FAQ.html