Re: JIT compiling with LLVM v9.0

On Tue, Jan 30, 2018 at 01:46:37PM -0500, Robert Haas wrote:
> On Mon, Jan 29, 2018 at 1:40 PM, Andres Freund <andres(at)anarazel(dot)de> wrote:
> > It's an optional dependency, and it doesn't increase build time
> > that much... If we were to move the llvm interfacing code to a
> > .so, there'd not even be a packaging issue, you can just package
> > that .so separately and get errors if somebody tries to enable
> > LLVM without that .so being installed.
>
> I suspect that would be really valuable. If 'yum install
> postgresql-server' (or your favorite equivalent) sucks down all of
> LLVM,

As I understand it, LLVM is organized in such a way as not to require
this. Andres, am I understanding correctly that what you're using
doesn't require much of LLVM at runtime?

> some people are going to complain, either because they are
> trying to build little tiny machine images or because they are
> subject to policies which preclude the presence of a compiler on a
> production server. If you can do 'yum install postgresql-server'
> without additional dependencies and 'yum install
> postgresql-server-jit' to make it go faster, that issue is solved.

Would you consider it solved if there were some very small part of the
LLVM (or similar JIT-capable) toolchain added as a dependency, or does
it need to be optional into a long future?

> Unfortunately, that has the pretty significant downside that a lot of
> people who actually want the postgresql-server-jit package will not
> realize that they need to install it, which sucks.

It does indeed.

Best,
David.
--
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778

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