On Mon, Oct 12, 2009 at 1:59 PM, Tom Lane wrote:
> Robert Haas writes:
>> On Sun, Oct 11, 2009 at 12:35 PM, Tom Lane wrote:
>>> Of course the downside of changing it is that queries that worked fine
>>> before might work differently (and much slower) now; first because not
>>> flattening the sub
Robert Haas writes:
> On Sun, Oct 11, 2009 at 12:35 PM, Tom Lane wrote:
>> Of course the downside of changing it is that queries that worked fine
>> before might work differently (and much slower) now; first because not
>> flattening the sub-select might lead to a worse plan, and second because
>
Robert Haas writes:
> On Sun, Oct 11, 2009 at 12:35 PM, Tom Lane wrote:
>> It's an entirely trivial code change either way. I'm inclined to think
>> that we should prevent flattening, on the grounds of least astonishment.
> It seems like this is somewhat related to the question of embedding an
On Sun, Oct 11, 2009 at 12:35 PM, Tom Lane wrote:
> I'm fooling around with pushing FOR UPDATE locking into a new plan node
> type, and I just noticed a behavior that seems a bit bogus.
> Historically we have dealt with FOR UPDATE in sub-selects by flattening
> the sub-select if we could, because
Markus Wanner writes:
> BTW: how do other databases deal with this? Anything of relevance in the
> SQL standards?
SQL99 treats FOR UPDATE as an attribute of DECLARE CURSOR, so there's
no way for it to appear in a sub-select per spec. (In general our
approach to FOR UPDATE is only loosely related
Hi,
Tom Lane wrote:
> It's an entirely trivial code change either way. I'm inclined to think
> that we should prevent flattening, on the grounds of least astonishment.
Yeah, I also tend towards making FOR UPDATE an optimization fence
(that's how I understood the non-flattening approach). While i
I'm fooling around with pushing FOR UPDATE locking into a new plan node
type, and I just noticed a behavior that seems a bit bogus.
Historically we have dealt with FOR UPDATE in sub-selects by flattening
the sub-select if we could, because the alternative was to fail
altogether. For example, consi
