Re: max_connections, solaris semaphores and initdb

Isaac Vetter <ivetter@math.purdue.edu> writes:
> Yes. I've restarted. Even rebooted to have the /etc/system changes take
> effect. My concern is that there's a value somewhere that quietly sets
> an upper limit on what max_connections can be, that is determined from
> kernel settings when initdb is run.

Well, you're mistaken: if the system can't support the specified
max_connections then it will fail at postmaster start, not silently
reduce the parameter value.

It's certainly possible to fall foul of a kernel process-count
restriction at runtime, but the message would look like "fork failed",
not the one you're reporting.

I think you've messed up changing the effective setting of
max_connections somehow.  Are you sure you edited the right copy of
postgresql.conf?

> 0) Is this correct? Does initdb set an unchangeable value that quietly
> limits the high end of max_connections?

The only thing that initdb does is put a value for max_connections into
the initial postgresql.conf file, which it chooses by experimenting to
see whether the postmaster will start with various settings.  No hidden
magic.

            regards, tom lane