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Re: Stupid question on Read Committed Isolation Level

From: "Marc G(dot) Fournier" <scrappy(at)postgresql(dot)org>
To: "Jeroen T(dot) Vermeulen" <jtv(at)xs4all(dot)nl>
Cc: "Marc G(dot) Fournier" <scrappy(at)postgresql(dot)org>,pgsql-hackers(at)postgresql(dot)org
Subject: Re: Stupid question on Read Committed Isolation Level
Date: 2004-01-29 19:27:06
Message-ID: 20040129152653.C6922@ganymede.hub.org (view raw or flat)
Thread:
Lists: pgsql-hackers
On Thu, 29 Jan 2004, Jeroen T. Vermeulen wrote:

> On Thu, Jan 29, 2004 at 02:07:25PM -0400, Marc G. Fournier wrote:
> >
> > "If two such transactions concurrently try to change the balance of
> > account 12345, we clearly want the second transaction to start from the
> > updated version of the account's row"
> >
> > To me, I read this as the first transaction has not yet committed, but the
> > second sees its changes ... so if second commitst, and first hasn't yet,
> > second commits with seconds changes + firsts changes, but what if first
> > aborts?
>
> There's the rub--it doesn't say the part about "has not yet committed,"
> although I can see how you could read it that way.

I would say that "two such transactions concurrently" heavily implies
such, no? :)


----
Marc G. Fournier           Hub.Org Networking Services (http://www.hub.org)
Email: scrappy(at)hub(dot)org           Yahoo!: yscrappy              ICQ: 7615664

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