Re: [BUGS] Status of issue 4593

Jeff Davis wrote:
> On Mon, 2009-01-12 at 13:35 -0500, Tom Lane wrote:
> > I think the behavior Lee is expecting is only implementable with a
> > full-table write lock, which is exactly what FOR UPDATE is designed
> > to avoid. There are certain properties you don't get with a partial
> > lock, and in the end I think we can't do much except document them.
> > We have LOCK TABLE for those who need the other behavior.
> >
>
> Lee said specifically that he's not using LIMIT, and there's already a
> pretty visible warning in the docs for using LIMIT with FOR UPDATE.
> Also, using LIMIT + FOR UPDATE has a dangerous-looking quality to it (at
> least to me) that would cause me to do a little more investigation
> before relying on its behavior.
>
> I'm not pushing for FOR UPDATE + ORDER BY to be blocked outright, but I
> think it's strange enough that it should be considered some kind of
> defect worse than the cases involving LIMIT that you mention.

I have added the attached documentation mention to CVS HEAD and 8.3.X.
If people want a TODO entry or to issue a WARNING message on use, please
let me know. This does seem similar to the FOR UPDATE / LIMIT issue so
I handled it similarly.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

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