"Baker, Keith [OCDUS Non-J&J]" <kbak...@its.jnj.com> writes:
> I propose that a QNX 6.5 port be introduced to PostgreSQL.

Hmm ... you're aware that there used to be a QNX port?  We removed it
back in 2006 for lack of interest and maintainers, and AFAIR you're
the first person to show any interest in reintroducing it since then.

I'm a bit concerned about reintroducing something that seems to have so
little usage, especially if the port is going to be as invasive as you
suggest:

> *         QNX lacks System V shared memory: I created 
> "src/backend/port/posix_shmem.c" which replaces System V calls (shmget, 
> shmat, shmdt, ...) with POSIX calls (shm_open, mmap, munmap, shm_unlink)

This isn't really acceptable for production usage; if it were, we'd have
done it already.  The POSIX APIs lack any way to tell how many processes
are attached to a shmem segment, which is *necessary* functionality for
us (it's a critical part of the interlock against starting multiple
postmasters in one data directory).

> *         QNX lacks sigaction SA_RESTART: I modified "src/include/port.h" to 
> define macros to retry system calls upon EINTR (open,read,write,...) when 
> compiled on QNX

That's pretty scary too.  For one thing, such macros would affect every
call site whether it's running with SA_RESTART or not.  Do you really
need it?  It looks to me like we just turn off HAVE_POSIX_SIGNALS if
you don't have SA_RESTART.  Maybe that code has bit-rotted by now, but
it did work at one time.

                        regards, tom lane


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