On Fri, Feb 10, 2012 at 2:35 AM, Gary Chambers <gwchamb@xxxxxxxxxxx> wrote: > Is it possible that > Postgres is not receiving a meaningful response with respect to > ExclusiveLock locking (i.e. unable to really obtain an ExclusiveLock) due to > VM "disk" residing on an NFS mount? pg_advisory_unlock (along with the other functions in that family) works on a set of mythical objects with no actual meaning beyond what the database administrator chooses to give them. You lock and unlock these ethereal "things", just numbers off a set of tables, with no relationship to NFS mounts, tables, records, or anything else. In (the current iteration of) the priority-queue I wrote for work, each queue-pumping process takes an exclusive lock on a "partition", where a partition is one fraction of the available ID space, using modulo arithmetic. At least, that's what I, the programmer, see; to Postgres, it just takes an exclusive lock on (42,64) or some other pair of numbers. That lock will succeed or fail only on the basis of other advisory lock calls, nothing else can affect it. Chris Angelico -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
