Re: pgsql: Add documentation for the JIT feature.

Greetings,

* Andres Freund (andres(at)anarazel(dot)de) wrote:
> On 2018-03-29 13:26:31 -0400, Robert Haas wrote:
> > On Thu, Mar 29, 2018 at 9:44 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> > > I'd go a little further and drop "JIT" from user-facing documentation
> > > altogether. Instead refer to the feature as "compilation of expressions"
> > > or some such. JIT is just jargon. Plus, the timing of the compilation is
> > > actually the least important property for our purpose.
> >
> > I agree that talking about JIT compilation (or just-in-time
> > compilation) would be better than talking just about JIT, but refusing
> > to mention JIT seems counter-productive to me. There are a lot of
> > people who know what just-in-time compilation is and will not realize
> > that "compilation of expressions" refers to any such technology. If
> > you don't know what it is, you can Google it. Just typing "jit" into
> > Google produces a stupid urban dictionary hit and then this:
> > https://en.wikipedia.org/wiki/Just-in-time_compilation -- and that
> > contains useful information that you'll never find if you search for
> > "compilation of expressions".
> >
> > Also, in a way, you could argue that v10 already did "compilation of
> > expressions". It didn't compile them to machine language, true, but
> > it translated them into a form which is faster to execute, and which
> > is at least arguably a form of bytecode. It's not going to be clear,
> > even to an expert, that "compilation of expressions" means something
> > other than that, but if you say JIT, then all of a sudden people know
> > what we're talking about.
> >
> > I agree that JIT is jargon, but it's pretty commonly-used jargon.
>
> Precisely this. I'm very strongly against just saying "expression
> compilation", it's just too imprecise. As Robert mentions it could refer
> to what we do in v10, it could refer to ahead of time compilation of PL
> functions, and it doesn't include compiling tuple deforming. Nor will
> it describe compiling sorting, copy or whatnot.
>
> I'm very open however to replacing JITing with JIT compiling and smilar
> substitutions.

What we've done elsewhere when there's been similar jargon is to say
something along the lines of:

"compiling of routines (also known as Just-In-Time or JIT compilation)"

Thanks!

Stephen