Re: Posix Shared Mem patch

> This can be trivially reproduced if one runs an old (SysV shared memory-based) postgresql alongside a potentially newer postgresql with a smaller SysV segment. This can occur with applications that bundle postgresql as part of the app.

I'm not saying it doesn't happen at all.  I'm saying it's not the 80%
case.

So let's fix the 80% case with something we feel confident in, and then
revisit the no-sysv interlock as a separate patch.  That way if we can't
fix the interlock issues, we still have a reduced-shmem version of Postgres.

-- 
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com