Thus spake The Hermit Hacker <[EMAIL PROTECTED]>:
> When Tor suggested changing this to me, he mentioned "This reduces the
> address space available for userland processes, but very few applications
> need more than 1 GB for data in a single process." ... now, if I'm
> understanding this correctly, if I set it to 512, a single process won't
> be able to exceed 2GB (*very* unlikely), but what happens if it does?
> Does the process just crash, but the system remains running?

As des mentioned, allocations will fail and the rest depends on
how the application handles that.

> > Pthreads in 4-STABLE uses the start of the main stack as a basis
> > for determining where to put stacks for individual threads that
> > are spawned.  The value of KVA_PAGES used to be statically
> > compiled into pthreads, so you would have to recompile libc every
> > time you changed KVA_PAGES.  Peter Wemm tried to fix this some
> > time ago by reading the value from sysctl instead, but his fix is
> > incomplete.  The patch in the following PR has been verified (not
> > by me) to fix the problem.  Hopefully it has not been subject to
> > bit rot over the last few months.
> 
> 'K, but as long as I install/upgrade both kernel and world at the same
> time, there won't be a problem, right ... ?

Right.

> > >   Similar was happening to the mysqld daemon ...
> >
> > Random naive question: Postgresql spawns separate processes
> > instead of using threads, doesn't it?  How has that worked out,
> > and is it expected to change?
> 
> Not expected to change, and works quite well ... there has been alot of
> work to reduce the start time for the process(es), which used to be alot
> of the complaints concerning 'seperate processes' ... there are ppl
> talking about working towards the Apache2 model (I'm one of them) where
> each process would still only handle one connection, but would be able to
> offload some of the processing to other threads, so that they could work
> in parrellel ...

Cool.  I wouldn't expect process startup time to be a big deal
unless you have new clients initiating new connections like mad,
and I hope that isn't a common case.  (Then again, I'm not a
database person, and I don't know how e.g. PHP might interact with
the database.)  The reliability advantage of multiple processes
seems important as well.  In any case, I will migrate over to the
correct lists if I have any more questions about postgresql.  ;-)
Thanks.

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