AFAIK, the only systems supported by Postgres that this patch won't
work on are NetBSD and OpenBSD.
The POSIX calls free the user from the SHMMAX and SHMALL limitations
of the SysV shared memory calls on platforms that support it. Since
this still takes one SysV segment, SHMMNI can still be reached on
some platforms if a ton of databases are opened simultaneously (i.e.
256 on Linux and Solaris, 100 on SCO Unix, 512 on HP-UX, 32 on Mac OS
X, unlimited on FreeBSD). This is the case without the patch anyhow.
Chris Marcellino
On Mar 3, 2007, at 9:09 AM, Joshua D. Drake wrote:
If you have the need to ship a product with Postgres embedded in
it and
are unable to change kernel settings (like myself), this might be
of use
to you. I have tested all of the failure situations I could think
of by
various combinations of deleting lockfiles while in use, changing the
PID inside the lockfile and trying to restart and run more than one
postmaster simultaneously.
Of course, this since this requires both POSIX and SysV shared
memory,
this doesn't increase the portability of Postgres which might make it
less appropriate for mass distribution; I thought I would put it out
there for any feedback either way.
Well that depends, what systems don't use (or have) POSIX shared
memory?
This sounds very interesting to me. Oddly enough I went to do some
digging on what various differences and I came up with:
http://www.nabble.com/POSIX-shared-memory-support-t3298386.html
Which happens to be you ;)
Sincerely,
Joshua D. Drake
Thanks again,
Chris Marcellino
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