Re: fork/exec patch - Mailing list pgsql-patches

From Tom Lane
Subject Re: fork/exec patch
Date
Msg-id 5557.1071459249@sss.pgh.pa.us
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In response to Re: fork/exec patch  (Bruce Momjian <pgman@candle.pha.pa.us>)
Responses Re: fork/exec patch
List pgsql-patches
Bruce Momjian <pgman@candle.pha.pa.us> writes:
> Agreed, added to the Win32 status page:
>     * remove per-backend parameter file and move into shared memory

[itch]  I'm not sure that's an answer either; see my comments about how
the postmaster shouldn't depend on the contents of shared memory being
valid.

We could get away with the postmaster having a write-only relationship
to shared memory (put value of variable X into predetermined location
Y), but I don't think that helps.  It doesn't work for variable-size
values --- we certainly don't want the postmaster dependent on memory
allocation structures being valid within shared memory --- and what
about locks?  Do you want the postmaster writing shared values without
taking a lock, or relying on shared-memory lock structures to be valid
enough to not lock it up or crash it?  My answer to either of those is
"no way, Jose" ...

Writing temp files may actually be a cleaner solution than writing
shared memory, once we take these considerations into account.  My gripe
about race conditions was "I want to see how you solve this", and wasn't
intended to mean "I don't think that is soluble".

            regards, tom lane

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