Greg Smith <gsmith@gregsmith.com> writes:
> If there were ever any Linux distributions that increased this value from
> the tiny default, you might have a defensible position here (maybe
> Oracle's RHEL fork does, they might do something here). I've certainly
> never seen anything besides Solaris ship with a sensible SHMMAX setting
> for database use on 2008 hardware out of the box. It's really quite odd,
> but as numerous probes in this area (from the above in 2000 to Peter's
> recent Linux bugzilla jaunt) show the resistance to making the OS default
> to any higher is considerable.
I think the subtext there is that the Linux kernel hackers hate the SysV
IPC APIs and wish they'd go away. They are presently constrained from
removing 'em by their desire for POSIX compliance, but you won't get
them to make any changes that might result in those APIs becoming more
widely used :-(
Mind you, I find the SysV APIs uselessly baroque too, but there is one
feature that we have to have that is not in mmap(): the ability to
detect other processes attached to a shmem block.
regards, tom lane