Re: proposal: a validator for configuration files

Robert Haas <robertmhaas@gmail.com> writes:
> On Sat, Jul 16, 2011 at 10:04 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Robert Haas <robertmhaas@gmail.com> writes:
>>> Is there any way that we could get *rid* of custom_variable_classes?

>> Well, we could just drop it and say you can set any dotted-name GUC
>> you feel like.

> ...and the fact that we've made them set an extra GUC to shoot
> themselves in the foot hardly seems like an improvement.  I was more
> thinking along the lines of having loadable modules register custom
> variable classes at load time, through some sort of C API provided for
> that purpose, rather than having the user declare a list that may or
> may not match what the .so files really care about.

Well, we *do* have a C API for that, of a sort.  The problem is, what do
you do in processes that have not loaded the relevant extension?  (And
no, I don't like the answer of "let's force the postmaster to load every
extension we want to set any parameters for".)

I agree custom_variable_classes is conceptually messy, but it's a
reasonably lightweight compromise that gives some error checking without
requiring a lot of possibly-irrelevant extensions to be loaded into
every postgres process.
        regards, tom lane