Re: In PG12, query with float calculations is slower than PG11

On Fri, Feb 14, 2020 at 3:47 AM Andres Freund <andres(at)anarazel(dot)de> wrote:
> On 2020-02-13 13:40:43 -0500, Tom Lane wrote:
> > ... and pushed. One other change I made beyond those suggested
> > was to push the zero-divide ereport's out-of-line as well.
>
> Thanks!

Thank you all.

I repeated some of the tests I did earlier and things look good.

gcc-8
=====

HEAD

latency average = 296.842 ms

42.05% postgres postgres [.] ExecInterpExpr
15.14% postgres postgres [.] float8_accum
9.32% postgres libc-2.17.so [.] __isinf
7.32% postgres postgres [.] dsqrt
5.67% postgres postgres [.] float8mul
4.20% postgres postgres [.] ftod

11.7

latency average = 289.439 ms

41.52% postgres postgres [.] ExecInterpExpr
13.59% postgres libc-2.17.so [.] __isinf
10.98% postgres postgres [.] float8_accum
8.26% postgres postgres [.] dsqrt
6.17% postgres postgres [.] float8mul
3.65% postgres postgres [.] ftod

clang-7
=======

HEAD

latency average = 233.735 ms

43.84% postgres postgres [.] ExecInterpExpr
15.17% postgres postgres [.] float8_accum
8.25% postgres postgres [.] dsqrt
7.35% postgres postgres [.] float8mul
5.84% postgres postgres [.] ftod
3.78% postgres postgres [.] tts_buffer_heap_getsomeattrs

11.7

latency average = 221.009 ms

49.55% postgres postgres [.] ExecInterpExpr
12.05% postgres postgres [.] float8_accum
8.97% postgres postgres [.] dsqrt
6.72% postgres postgres [.] float8mul
5.62% postgres postgres [.] ftod
2.18% postgres postgres [.] slot_deform_tuple

HEAD and PG 11 are now comparable even when built with gcc.

Regards,
Amit