Re: Deadlock in Index (where index is B+ tree) Locking with Intention Locks
Date: Thu, 12 Dec 2002 10:20:37 -0800
Message-ID: <ew4K9.7$cw5.102_at_news.oracle.com>
"Novice" <6tc1_at_qlink.queensu.ca> wrote in message
news:b80e4a77.0212120907.7cfb153d_at_posting.google.com...
> And let's imagine the following scenario:
> T1 - IX(root) IX(B) IX(D) IX(H) X(P) X(H) X(D) X(B) U(P) U(H) U(D)
> U(B) U(root)
> T2 - IX(root) IX(B) IX(D) IX(H) X(O) X(H) X(D) X(B) U(O) U(H) U(D)
> U(B) U(root)
> T3 - IX(root) IX(B) IX(D) IX(G) X(N) X(G) X(D) X(B) U(N) U(G) U(D)
> U(B) U(root)
>
> There is no permutation I could find of the above that would result in
> deadlock.
>
> If you can think of a more simple set of transactions that would
> result in deadlock I would also be interested in that.
Is your protocol deadlock safe? Maybe. But it's not very interesting, since all your transactions are serialized on the root node. You need to unlock root node early, and then watch problem to happen! Received on Thu Dec 12 2002 - 19:20:37 CET