Re: [HACKERS] postmaster failure with 2-23 snapshot

> Tom Ivar Helbekkmo <tih@nhh.no> writes:
> > Looking more closely into it, the postmaster is trying to allocate 64
> > semaphores in four groups of 16, so I built a new kernel with a higher
> > limit, and it's now OK.
> > This is as it should be, I hope?  It's not a case of something being
> > misconfigured now, using semaphores instead of some other facility?
> 
> Yes, this is an intentional change --- I guess you haven't been reading
> the hackers list very closely.  The postmaster is now set up to grab
> all the semaphores Postgres could need (for the specified number of
> backend processes) immediately at postmaster startup.  Failing then
> for lack of semaphores seems a better idea than failing under load
> when you try to start the N+1'st client, which is what used to happen.
> 
> There has been some discussion of reducing the default number-of-
> backends limit to 32 so that a stock installation is less likely
> to run out of semaphores.

Tom, better lower that limit soon.  People are having trouble with the
snapshots.


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