Chris Richards <chris@infinite.io> writes:
> Oh the email spam :P
No problem. I'm starting to think that this isn't actually a Postgres
bug, but rather something funny with your kernel. The code in sysv_shmem
is certainly as fragile as can be, but I'm darned if I can find an
existing code path that would actually break it --- and the lack of other
complaints is pointing towards something funny with your system, too.
First off, does changing "huge_pages" in postgresql.conf alter the
behavior? (It defaults to "try", see what happens with "on" or "off".)
Second, I notice that you've got
> Hugepagesize: 1048576 kB
which is just enormous. PG is only going to request circa 140MB given
the settings you mentioned. We've seen reports of kernel bugs that cause
mmap() to fail for requests that aren't a multiple of the hugepage size,
but I've not heard that mmap() might succeed and then munmap() fail.
That seems like what's happening to you though.
regards, tom lane