Re: 7.3b2 initdb fails with semaphore error (solved)

On Tue, 1 Oct 2002, Tom Lane wrote:

> Mark Stosberg <mark@summersault.com> writes:
> > I think the bug here is that this message advertises that I can change
> > the "max_connections" parameter to address this, but there does not
> > appear to be a way to do this.  The max_connections option is located
> > on my system at /usr/local/share/postgresql/postgresql.conf.sample
> > (prior to initdb)
>
> Hmm ... actually, I don't think the max_connections parameter is used
> during standalone operation.  It looks like the code uses a hardwired
> value of "16".  We could reduce that (there's probably no good reason
> why it's not "1"), but I suspect your SEMMAX parameter is so small
> it will fail anyway :-(
>
> Would you try changing "16" to "1" in InitCommunication() in
> src/backend/utils/init/postinit.c, and see if that helps on your
> setup?

Tom,

I tried this change, and was able to successfully "initdb" after that,
and then run "psql" after that. I'm running this installation on a home
machine for light use, so I may not need 16 backends anyway.

If you're correct that there is no need to have more than 1 backend
during "initdb", then perhaps this could be turned into a patch. My
simple patch is below:

 -mark

http://mark.stosberg.com/

################################

--- postinit.c.orig     Wed Oct  2 12:56:13 2002
+++ postinit.c  Wed Oct  2 12:56:42 2002
@@ -176,7 +176,7 @@
                 * postmaster.  Create private "shmem" and semaphores.  Setting
                 * MaxBackends = 16 is arbitrary.
                 */
-               CreateSharedMemoryAndSemaphores(true, 16, 0);
+               CreateSharedMemoryAndSemaphores(true, 1, 0);
        }
 }