On Mon, 31 Jul 2000 17:23:08 +0100, Lahooti, Hamid
<[EMAIL PROTECTED]> wrote:
><[EMAIL PROTECTED]> wrote:
>I think I was giving you more credit than you deserve. I don't know
>whether it's your English or real lack of DBMS understanding here but
>it seems to me you have the wrong end of the stick. You don't even
>seem to know what a database resource deadlock is and how it comes about.
LOL.... :-)
Ok, this isn't working. Let's do it backwards then:
explain in as much detail as possible the notions of "pessmistic
concurrency control" and "optimistic concurrency control", and how they
differ. In particular, detail how they handle conflicts between
transactions that want to not only access, but also modify, the same
rows of data.
And at the same time..
>Once again:
>
>TX1 updates DB resource A, and waits on DB resource B
>TX2 updates DB resource B, and waits on DB resource A
>
>Deadlock.
.. explain why TX2 in a DB using optimistic concurrency control needs to
"wait" for resource A.
>
>Now is that really that difficult for you to grasp?
Nope. Crystal clear, and the answer is contained in my previous posting.
/Rickard
--
Rickard �berg
Email: [EMAIL PROTECTED]
http://www.telkel.com
http://www.jboss.org
http://www.dreambean.com
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