Re: BUG #14206: Switch to using POSIX semaphores on FreeBSD

Maxim Sobolev <sobomax@sippysoft.com> writes:
> From the man semopt:
>      [EINVAL]           No semaphore set corresponds to semid, or the process
>                         would exceed the system-defined limit for the number
>                         of per-process SEM_UNDO structures.

> AFAIK we've been hitting the second cause there. This is with FreeBSD 10.3
> and postgresql 9.2.16 specifically. We've also seen this with 9.1 I think,
> but I am not 100% sure. The specific limit that got exceeded
> was kern.ipc.semmnu.

We never ask semop(2) for SEM_UNDO, so are you sure this isn't a kernel
bug?  I've never heard of such a report on any other platform.

            regards, tom lane