Re: WIP: Faster Expression Processing and Tuple Deforming (including JIT)

On Tue, Dec 6, 2016 at 11:10:59AM -0800, Andres Freund wrote:
> > I concur with your feeling that hand-rolled JIT is right out. But
> > I'm not sure that whatever performance gain we might get in this
> > direction is worth the costs.
>
> Well, I'm not impartial, but I don't think we do our users a service by
> leaving significant speedups untackled, and after spending a *LOT* of
> time on this, I don't see much other choice than JITing. Note that
> nearly everything performance sensitive is moving towards doing JITing
> in some form or another.

Agreed, we don't really have a choice. After all the optimizations we
have done to so many subsystems, our executor is relatively slow and is
a major drag on our system, specifically for long-running queries. The
base problem with the executor are the state machines at so many levels,
and we really can't optimize that while keeping a reasonable maintenance
burden.

This is where JIT and LLVM help. I outlined two external projects that
were researching this in this blog entry:

http://momjian.us/main/blogs/pgblog/2016.html#April_1_2016

I am excited to now be seeing WIP code.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

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