On Wed, Oct 3, 2012 at 12:41:37PM -0400, Tom Lane wrote: > I wrote: > > Alvaro Herrera <[email protected]> writes: > >> Noticed while perusing > >> http://lwn.net/Articles/518306/ > > > I'm afraid Brian was just looking for an excuse to dump on Apple. We > > have a lot of years of Postgres experience showing that fork() works > > fine on OS X. > > BTW, I think the commenter at the bottom of the thread puts his finger > on the core of the real problem: > > > I'd wager most libraries are not fork safe, including such libraries > > as SQLite as mentioned in the SQLite FAQ. Libraries that talk to the > > outside world contain much state that is not safe to share. > > To bring that closer to home, suppose you have a program with an open > database connection in libpq, and you fork(), and then parent and child > both try to use the connection. How well would that work? Is it the > fault of fork()? > > I think Apple is just pointing out that their framework libraries have > similar issues.
Yes, but those framework libraries are typically supposed to prevent such problems from being seen by applications calling them. This is certainly sloppy practice on Apple's part, and it leave us wondering if we are using anything that might be a problem. The bottom line is that we don't know. Libraries are supposed to document these limitations, as we do with libpq. I wonder if they just documented fork() and now don't feel they need to document these limitations per-library. Anyway, I agree that we need to see a failure before adjusting anything. -- Bruce Momjian <[email protected]> http://momjian.us EnterpriseDB http://enterprisedb.com + It's impossible for everything to be true. + -- Sent via pgsql-hackers mailing list ([email protected]) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
