Pre-allocation of shared memory ...

There is a problem which occurs from time to time and which is a bit
nasty in business environments.
When the shared memory is eaten up by some application such as Apache
PostgreSQL will refuse to do what it should do because there is no
memory around. To many people this looks like a problem relatd to
stability. Also, it influences availability of the database itself.

I was thinking of a solution which might help to get around this problem:
If we had a flag to tell PostgreSQL that XXX Megs of shared memory
should be preallocated by PostgreSQL. The database would the sure that
there is always enough memory around. The problem is that PostgreSQL had
to care more about memory consumption.

Of course, the best solution is to put PostgreSQL on a separate machine
but many people don't do it so we have to live with memory leaks caused
by other software (we have just seen a nasty one in mod_perl).

Does it make sense?

Regards,

Hans

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