Re: reducing the footprint of ScanKeyword (was Re: Large writable variables)

Hi,

On 2019-01-04 16:43:39 -0500, Tom Lane wrote:
> Joerg Sonnenberger <joerg(at)bec(dot)de> writes:
> >> * What's the generator written in? (if the answer's not "Perl", wedging
> >> it into our build processes might be painful)
>
> > Plain C, nothing really fancy in it.
>
> That's actually a bigger problem than you might think, because it
> doesn't fit in very nicely in a cross-compiling build: we might not
> have any C compiler at hand that generates programs that can execute
> on the build machine. That's why we prefer Perl for tools that need
> to execute during the build. However, if the code is pretty small
> and fast, maybe translating it to Perl is feasible. Or perhaps
> we could add sufficient autoconfiscation infrastructure to identify
> a native C compiler. It's not very likely that there isn't one,
> but it is possible that nothing we learned about the configured
> target compiler would apply to it :-(

I think it might be ok if we included the output of the generator in the
buildtree? Not being able to add keywords while cross-compiling sounds like
an acceptable restriction to me. I assume we'd likely grow further users
of such a generator over time, and some of the input lists might be big
enough that we'd not want to force it to be recomputed on every machine.

Greetings,

Andres Freund