Re: Patch for 8.5, transformationHook

Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> writes:
> 2009/4/11 Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>:
>> Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> writes:
>>> I am sending small patch, that allows hooking transformation stage of parser.
>>
>> Isn't this the exact same patch we rejected several months ago?

> What I remember, You had some objections about different behave before
> and after loading an library.

No, I was complaining that a hook right there is useless and expensive.
transformExpr() is executed multiple times per query, potentially a very
large number of times per query; so even testing to see if a hook exists
is not a negligible cost. And I have not seen anything I regard as a
convincing demonstration of use-case that can't be handled as well or
better in some other way.

regards, tom lane