Re: JIT compiling with LLVM v9.0

Hi,

On 2018-01-31 15:48:09 +1300, Thomas Munro wrote:
> On Wed, Jan 31, 2018 at 3:05 PM, Andres Freund <andres@anarazel.de> wrote:
> > I'm not quite sure I understand. You mean have it display whether
> > available? I think my plan is to "just" set jit_expressions=on (or
> > whatever we're going to name it) fail if the prerequisites aren't
> > available. I personally don't think this should be enabled by default,
> > definitely not in the first release.
> 
> I assumed (incorrectly) that you wanted it to default to on if
> available, so I was suggesting making it obvious to end users if
> they've accidentally forgotten to install -jit.  If it's not enabled
> until you actually ask for it and trying to enable it when it's not
> installed barfs, then that seems sensible.

I'm open to changing my mind on it, but it seems a bit weird that a
feature that relies on a shlib being installed magically turns itself on
if avaible. And leaving that angle aside, ISTM, that it's a complex
enough feature that it should be opt-in the first release... Think we
roughly did that right for e.g. parallellism.

Greetings,

Andres Freund