Jan de Visser <jdevisser@digitalfairway.com> writes:
> So what could make my transaction decide to wait for that other tx?
Usually what this indicates is blocking to acquire a row-level lock,
eg that transaction is waiting to see if it can update a row that the
other one already updated. In 8.1 and later you can find out which row
is contended for by seeing what row-level lock is held by the *waiting*
transaction (yes, really, not the waited-for one).
regards, tom lane