korry wrote: > > > You never need to reduce it to a shared lock. On postmaster startup, > > > try to lock the sentinel byte (one byte past the end-of-file). If you > > > can lock it, you know that no other postmaster has that byte locked. If > > > you can't lock it, another postmaster is running. It is an atomic > > > operation. > > > > This doesn't work if the postmaster dies but a backend continues to run, > > which is arguably the most important case we need to protect against. > > I may be confused here, but I don't see the problem - byte-range locks > are not inherited across a fork. A backend would never hold the lock, a > backend would never even look for the lock.
Well, you are wrong here. We _want_ every backend to hold a shared lock. We need to stop a postmaster from starting if there is a backend running that was started by a no-longer-running postmaster. -- Alvaro Herrera http://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
