Peter Eisentraut <peter_e@gmx.net> writes:
> On 8/10/12 7:48 PM, Dimitri Fontaine wrote:
>> What about having single user mode talk fe/be protocol, and talk to it via a UNIX pipe, with pg_upgrade starting the
singleuser backend as a subprocess?
> I think that's essentially equivalent to starting the server on a
> Unix-domain socket in a private directory. But that has been rejected
> because it doesn't work on Windows.
> The question in my mind is, is there some other usable way on Windows
> for two unrelated processes to communicate over file descriptors in a
> private and secure way?
You're making this unnecessarily hard, because there is no need for the
two processes to be unrelated.
The implementation I'm visualizing is that a would-be client (think psql
or pg_dump, though the code would actually be in libpq) forks off a
process that becomes a standalone backend, and then they communicate
over a pair of pipes that were created before forking. This is
implementable on any platform that supports Postgres, because initdb
already relies on equivalent capabilities.
regards, tom lane