Re: Select For Update and Left Outer Join

On Jul 11, 2011, at 11:55 AM, "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov> wrote:
> Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>
>> I find these responses to be a bit off point.
>
> The OP is basically looking for what Florian tried to implement.
> This is perhaps a *bit* off point, but arguably not more than
> pointing someone who is requesting planner hints in another
> direction. And someone thought the issues were related here:
>
> http://archives.postgresql.org/pgsql-hackers/2010-12/msg01792.php
>
> ;-)

Well, fair enough. I thought of the connection between this request and Florian's work, too. I would very much like to support what he proposed, but it doesn't appear viable without a heapam rewrite, or maybe a lock manager rewrite. However, I think that's a somewhat separate question from whether we need to forbid SFU on the outer side of a join.

Tom's question seems to me to be right on target: what semantics do our competitors assign to this construct? And do they broadly agree with each other?

>> Evidently our competition does not agree
>
> Neither on this nor on planner hints. ;-)

Well, we are a pretty smart group of people. But I don't think we should completely ignore what other people are doing, on any topic.

...Robert