Re: some question about deadlock

"ipig" <ipig@ercist.iscas.ac.cn> writes:
>    In your example, it seems that process B is the first such waiter( the request of B conflicts AccessShareLock).

No.  Better go study
http://developer.postgresql.org/docs/postgres/explicit-locking.html#LOCKING-TABLES

After looking at the example again, consider the further assumption
that C already has AccessShareLock (which is certainly a valid
configuration).  Then A *must* queue between C and D; there is no
other valid order to grant the requests in.
        regards, tom lane