Re: Posix Shared Mem patch - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Posix Shared Mem patch
Date
Msg-id 20486.1340769649@sss.pgh.pa.us
Whole thread Raw
In response to Re: Posix Shared Mem patch  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: Posix Shared Mem patch  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-hackers
Robert Haas <robertmhaas@gmail.com> writes:
> So, here's a patch.  Instead of using POSIX shmem, I just took the
> expedient of using mmap() to map a block of MAP_SHARED|MAP_ANONYMOUS
> memory.  The sysv shm is still allocated, but it's just a copy of
> PGShmemHeader; the "real" shared memory is the anonymous block.  This
> won't work if EXEC_BACKEND is defined so it just falls back on
> straight sysv shm in that case.

Um.  I hadn't thought about the EXEC_BACKEND interaction, but that seems
like a bit of a showstopper.  I would not like to give up the ability
to debug EXEC_BACKEND mode on Unixen.

Would Posix shmem help with that at all?  Why did you choose not to
use the Posix API, anyway?
        regards, tom lane


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