Re: [HACKERS] Time to drop old-style (V0) functions?

On 2016-12-20 10:44:35 +0100, Pavel Stehule wrote:
> 2016-12-20 10:28 GMT+01:00 Andres Freund <andres@anarazel.de>:
>
> > On 2016-12-20 01:14:10 -0800, Andres Freund wrote:
> > > On 2016-12-20 09:59:43 +0100, Pavel Stehule wrote:
> > > > In this case some benchmark can be very important (and interesting). I
> > am
> > > > not sure if faster function execution has significant benefit on
> > Vulcano
> > > > like executor.
> > >
> > > It's fairly to see function calls as significant overhead. In fact, I
> > > moved things *away* from a pure Vulcano style executor, and the benefits
> > > weren't huge, primarily due to expression evaluation overhead (of which
> > > function call overhead is one part).  After JITing of expressions, it
> > > becomes even more noticeable, because the overhead of the expression
> > > evaluation is reduced.
> >
>
> For me a Vulcano style is row by row processing. Using JIT or not using has
> not significant impact.
>
> Interesting change can be block level processing.

I don't think that's true. The largest bottlenecks atm have relatively
little to do with block level processing. I know, because I went
there. We have so many other bottlenecks that row-by-row processing
vanishes behind them.  Without changing the tuple flow, the performance
with either applied or posted patches for TPCH-Q1 already went up by
more than a factor of 2.5.

Anyway, this seems like a side-track discussion, better done in another
thread.

Andres