Thanks for the helpful comment, Patrick. I've not looked at database processes closely since taking an Oracle course a year ago, but now I want to dig in. The only changes I've made to postgresql.conf are those recommended by the openacs documentation, including increasing shared memory limit for postgres to: kernel.shmmax = 134217728. Where the docs suggest: shared_buffers = 15200 I got error messages above 7600 so left that at 7600. I set sort_mem = 32168. When I added a fifth instance, the flow of error messages when starting openacs was noticeably slower and then halted, and so, as I can wait for that instance until I buy more memory, I limited myself to four instances. I would guess that the appropriate question, and use of this forum, is to ask how I might best benchmark my setup: how people go about checking postgres and what values to look for. I will read up on the postgres application design and study the docs, but what I haven't found yet is a "howto" relevant to dotlrn/openacs for newbies, those of us who aren't yet "real" programmers, that might direct us to the major performance indicators, let us know how deep we need to go so we can study that and then move on to the zillion other things we need to do. Have you come across such a thing, or maybe you might volunteer to sketch what it might include? MANY thanks!
Bruce
