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Re: spontaneous rollback and retry?

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Thu, 8 Jan 2004 16:40:29 -0000
Message-ID: <btk15v$pca$1$8302bc10@news.demon.co.uk>

I've just realised that my comments have a fatal flaw - when you start a parallel DML, the locking your session does should make it impossible for another session do an update that causes the implicit restart. (Maybe it's broken in your version, or for the merge command, I've only been testing with the ordinary update command in the past).

Which version of Oracle are you on, 9.0. or 9.2 ? Are you updating a partitioned table ?
And you could you tell us what TX, TM and PS locks appear in v$lock when you run the update. (If you have a high degree of parallelism, you only need list the locks from one of the slave SIDs).

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Jonathan Lewis
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"Jonathan Lewis" <jonathan_at_jlcomp.demon.co.uk> wrote in message
news:btj5b8$6d7$1$8300dec7_at_news.demon.co.uk...

>
> I haven't tested in parallel yet, so may be
> wrong, but I think what you're seeing is
> Oracle trying to do a consistent update.
>
> Consider the scenario:
> 4 rows in table with value 'X'
> Session 1 does:
> update table set 'X' to 'Y';
>
> Session 2 manages to do
> update table 'X' to 'Y' in one row;
> commit;
>
> But session 2 does it's commit BEFORE
> session 1 gets to that one row.
>
Received on Thu Jan 08 2004 - 10:40:29 CST

Original text of this message

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