Re: SSI patch version 14

On 02/09/2011 06:25 PM, Robert Haas wrote:
> On Wed, Feb 9, 2011 at 10:38 AM, Markus Wanner <markus@bluegap.ch> wrote:
>> Thread based, dynamically allocatable and resizeable shared memory, as
>> most other projects and developers use, for example.

I didn't mean to say we should switch to that model.  It's just *the*
other model that works (whether or not it's better in general or for
Postgres is debatable).

> Or less invasively, a small sysv shm to prevent the double-postmaster
> problem, and allocate the rest using POSIX shm.

..which allows ftruncate() to resize, right?  That's the main benefit
over sysv shm which we currently use.

ISTM that addresses the resizing-of-the-overall-shared-memory question,
but doesn't that require dynamic allocation or some other kind of
book-keeping?  Or do you envision all subsystems to have to
re-initialize their new (grown or shrunken) chunk of it?

Regards

Markus Wanner