Re: Optimizing PostgreSQL with LLVM's PGO+LTO

=?UTF-8?Q?Jo=C3=A3o_Paulo_Labegalini_de_Carvalho?= <jaopaulolc@gmail.com> writes:
> I am facing issues when applying LTO to PostgreSQL as the produced binary
> seems broken (the server dies quickly after it has started). This is
> definitely a compiler bug, but I was wondering if anyone here  have
> experimented with LTO for PostgreSQL.

There are a lot of places where we're implicitly relying on
cross-compilation-unit optimizations NOT happening, because the
code isn't adequately decorated with memory barriers and the like.
So I wouldn't necessarily assume that the misbehavior you're seeing
represents anything that the compiler folks would consider a bug.

In the long run we might be interested in trying to make this
work better, but I don't know of anyone working on it now.

            regards, tom lane