Re: Make EXPLAIN generate a generic plan for a parameterized query

Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at> writes:
> [ 0001-Add-EXPLAIN-option-GENERIC_PLAN.v4.patch ]

I took a closer look at this patch, and didn't like the implementation
much. You're not matching the behavior of PREPARE at all: for example,
this patch is content to let $1 be resolved with different types in
different places. We should be using the existing infrastructure that
parse_analyze_varparams uses.

Also, I believe that in contexts such as plpgsql, it is possible that
there's an external source of $N definitions, which we should probably
continue to honor even with GENERIC_PLAN.

So that leads me to think the code should be more like this. I'm not
sure if it's worth spending documentation and testing effort on the
case where we don't override an existing p_paramref_hook.

regards, tom lane