On Sun, Apr 10, 2011 at 5:03 PM, A.M. <age...@themactionfaction.com> wrote: > To ensure that no two postmasters can startup in the same data directory, I > use fcntl range locking on the data directory lock file, which also works > properly on (properly configured) NFS volumes. Whenever a postmaster or > postmaster child starts, it acquires a read (non-exclusive) lock on the data > directory's lock file. When a new postmaster starts, it queries if anything > would block a write (exclusive) lock on the lock file which returns a > lock-holding PID in the case when other postgresql processes are running.
This seems a lot leakier than what we do now (imagine, for example, shared storage) and I'm not sure what the advantage is. I was imagining keeping some portion of the data in sysv shm, and moving the big stuff to a POSIX shm that would operate alongside it. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers