Re: [HACKERS] WIP: Faster Expression Processing v4

Hi,


On 2017-03-19 23:55:50 -0400, Tom Lane wrote:
> Andres Freund <andres@anarazel.de> writes:
> > I've been pondering if we can't entirely get rid of CaseTest etc, the
> > amount of hackery required seems not like a good thing. One way I'd
> > prototyped was to replace them with PARAM_EXEC nodes - then the whole
> > issue of them potentially having different values at different parts of
> > an expression vanishes because the aliasing is removed.
> 
> Yes, replacing all of that with Param slots had occurred to me too.
> We might want to keep the special parse node types for convenience in
> reverse-listing, but having them act just like PARAM_EXEC for execution
> purposes seems promising.

As long as that special parse-time node is part of the same value
numbering, that makes sense (could just name make it a subtype of param
ala PARAM_CASE).  I don't think we actually do anything useful in
ruleutils etc with either CaseTest or CoerceToDomainValue.

- Andres