Augustin Amann <augustin(at)waw(dot)com> writes:
> During lock, we could see things like this in log file:
> Process 5556 waits for ShareLock on transaction 14910066; blocked by
> process 4940.
What that really means is that the first process is waiting for a row
lock that's held by the second one --- that is, it's trying to update a
row that the second transaction has updated and not yet committed.
> Why waiting update are not simply queued ?
Uh, that's exactly what's happening.
regards, tom lane