Re: fork/exec

> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > Agreed.  We have to pass the shared memory address, but the
> rest should
> > be registered in shared memory somewhere and we can initialize those
> > values.  The old code used to point _using_ those memory
> pointers, but I
> > don't think that is necessary --- in fork/exec mode, we can just use
> > share memory to initialize the pointers properly.
>
> Yeah.  It might be useful to extend the shmem segment header (which at
> the moment is mostly just for identification) to hold one or two
> critical addresses, such as the address of the LWLock array.  But the
> index map used to work for this back when we had fork/exec in the Unix
> implementation, so it should be possible to make it work again without
> undue amounts of pain.
>
>             regards, tom lane


Understood.

One slight circular problem with that. Currently, ShmemInitStruct waits on a
lock (ShmemIndexLock), locks require the MyProc structure (set by
InitProcess), and InitProcess needs access to... a bunch of shared memory
structs :-)

Would it be possible to re-jig ShmemInitStruct to not require locking (at
least for backend initialization)? Other ideas?

Cheers,
Claudio

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