On Tue, Apr 10, 2007 at 03:52:00PM -0400, Tom Lane wrote: > Kris Kennaway <[EMAIL PROTECTED]> writes: > > On Tue, Apr 10, 2007 at 02:46:56PM -0400, Tom Lane wrote: > >> Oh, I'm sure the BSD kernel acts as you describe. But Mark's point is > >> that Postgres never has more than one process waiting on any particular > >> SysV semaphore, and so the problem doesn't really affect us. > > > To be clear, some behaviour that postgresql does with sysv semaphores > > causes wakeups of many processes at once. i.e. if you have 20 > > clients, you will get up to 20 wakeups. I haven't studied the precise > > cause of this, but it is empirically true. This is the scaling > > problem I described, and it's what mux's patch addresses. > > [ shrug... ] To the extent that that happens, it's Postgres' own issue, > and no amount of kernel rejiggering will change it. But I certainly > have no objection to a patch that fixes the kernel behavior ...
As we've discussed before, by far the bigger issue with postgresql performance on FreeBSD is the default setting of update_process_titles=on. Kris
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