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Home -> Community -> Usenet -> c.d.o.server -> Re: Single-statement 'write consistency' on read committed. Oh, really?
Hello Jonathan,
A very interesting question ...
3.
"Jonathan Lewis" <jonathan_at_jlcomp.demon.co.uk> wrote in message
news:bqdb6b$3dl$1$8300dec7_at_news.demon.co.uk...
>
> The issue is known, and has been discussed
[...skipped...]
So Oracle has gone
> for the approach:
> update
> if we find a problem
> rollback
> select for update
> update
> end if;
Let's call the transaction experiencing restarts a 'big' update transaction: I do not think Oracle performs a 'select for update' after the 'rollback' in your pseudo-code since the fact of the matter is that multiple concurrent transactions can and often do cause multiple restarts to happen in the 'big' update transaction. Had the internal 'select for update' been executed, the 'big' update transaction wouldn't have needed to restart multiple times as any concurrent intervenening transactions would've been blocked by such 'select for update'.
Rgds. Received on Sun Nov 30 2003 - 21:07:24 CST