Re: Query JITing with LLVM ORC

On Thu, Sep 22, 2022 at 10:35 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> =?UTF-8?Q?Jo=C3=A3o_Paulo_Labegalini_de_Carvalho?= <jaopaulolc@gmail.com> writes:
> > Good to know. I compiled from the REL_14_5 tag and did a simple experiment
> > to contrast building with and w/o passing --with-llvm.
> > I ran the TPC-C benchmark with 1 warehouse, 10 terminals, 20min of ramp-up,
> > and 120 of measurement time.
> > The number of transactions per minute was about the same with & w/o JITing.
> > Is this expected? Should I use a different benchmark to observe a
> > performance difference?
>
> TPC-C is mostly short queries, so we aren't likely to choose to use JIT
> (and if we did, it'd likely be slower).  You need a long query that will
> execute the same expressions over and over for it to make sense to
> compile them.  Did you check whether any JIT was happening there?

See also the proposal thread which has some earlier numbers from TPC-H.

https://www.postgresql.org/message-id/flat/20170901064131.tazjxwus3k2w3ybh%40alap3.anarazel.de