> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
>
> >TX1 and TX2 are two different transactions.
> >Optimistic locking:
> >having modified resource A, TX1 must read the timestamp of resource B
> >to establish whether it has been modified by another transaction,
> >but the (as yet uncommitted)transaction TX2 has an exclusive
> lock on B.
>
> "optimistic locking" and "exclusive" are hard to use in the same
> sentence. With pessimistic locking there are no exclusive
> locks. That's
> why its optimistic...
>
> (am I missing something obvious here, or!?)
>
Perhaps an optimistic app server and a pessimistic database can cause this
situation.
Are there any pessimistic databases?
> >Similarly TX2 is waiting to acquire a shared lock on
> resource A but it
> >must wait for TX1 to commit.
>
- Avi
--
s/\be(\w+)/e-\1/g;
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