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From: Merlin Moncure <[email protected]>
To: Tom Lane <[email protected]>
Cc: Heikki Linnakangas <[email protected]>
Cc: Alvaro Herrera <[email protected]>
Cc: Simon Riggs <[email protected]>
Cc: [email protected]
Cc: [email protected]
Subject: Re: FOR SHARE vs FOR UPDATE locks
Date: Fri, 1 Dec 2006 15:11:59 -0500
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
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On 12/1/06, Tom Lane <[email protected]> wrote:
> "Heikki Linnakangas" <[email protected]> writes:
> > Let's throw an error for now. We have to come back to this in 8.3, I think.
>
> After further thought I think we should also seriously consider plan C:
> do nothing for now.  We now realize that there have been related bugs
> since 8.0, namely that
>
>         begin;
>         select some rows for update;
>         savepoint x;
>         update the same rows;
>         rollback to x;
>
> leaves the tuple(s) not locked.  The lack of complaints about this from
> the field suggests that this isn't a huge problem in practice.  If we
> do make it throw an error I'm afraid that we will break applications
> that aren't having a problem at the moment.

imo, the most likely scenario would be a begin/exception/end block in
pg/sql. i would venture to guess that very little true savepointing
happens in practice.  maybe add a little note of caution pg/sql error
handling documentation?

merlin

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