Allowing SYSV shared memory to allocated more than 2GB

Justin Sherrill justin at
Sat Apr 30 10:30:07 PDT 2011

I have not yet built 2.11 binary pkgsrc packages yet (in part cause
they aren't different from 2.10 at this point), so this is a good time
for a break, if one is needed.

On Sat, Apr 30, 2011 at 7:39 AM, Jan Lentfer <Jan.Lentfer at> wrote:
> When trying to test PostgreSQL concurrency on Matt's Opteron 48 core box
> with 64 GB of RAM I encountered the problem, that I wasn't able to set
> kern.ipc.shmmax to more than 1,99 GB.
> In colloboration with Sascha Wildner I created the following patch which
> allows to address more >= 2GB of shared memory. I ran PostgreSQL 9.0.4 on a
> X86_64 VM w/ 4GB configured with shared_buffers set to 2 GB (PostgreSQL uses
> shared memory for other things so we are well above the previous 1,99
> limit).
> What isn't clear to Sascha and me: Do we need to bump the libc version
> because of this? Opinions please.
> Jan

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