Re: semaphore usage "port based"?

* Tom Lane (tgl(at)sss(dot)pgh(dot)pa(dot)us) wrote:
> BTW, Marc, it occurs to me that a workaround for you would be to create
> a separate userid for postgres to run under in each jail; then the
> regular protection mechanisms would prevent the different postmasters
> from interfering with each others' semaphore sets. But I think that
> workaround just makes it even clearer that the jail mechanism isn't
> behaving very sanely.

Just to toss it in there, I do this on some systems where we use Linux
VServers. It's just so that when I'm looking at a process list across
the whole system it's easy to tell which processes are inside which
vservers (since the only thing which should be running in a given
vserver is a single Postgres instance which should only be running with
the uid/gid corresponding to that vserver, and that uid/gid is recorded
in the host passwd file with a name associated with it since that's the
passwd file used when looking at all pids).

I also just double-checked with the Linux VServer folks and they confirm
that IPC inside the vserver are isolated from all the other IPCs on the
system.

Thanks,

Stephen