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

Fwiw, also tried the patch that Kuroda-san had posted yesterday.

On Fri, Feb 7, 2020 at 5:17 PM Amit Langote <amitlangote09(at)gmail(dot)com> wrote:
> Latency and profiling results:
>
> gcc 8 (gcc (GCC) 8.3.1 20190311 (Red Hat 8.3.1-3))
> ====
>
> 11.6
>
> latency average = 463.968 ms
>
> 40.62% postgres postgres [.] ExecInterpExpr
> 9.74% postgres postgres [.] float8_accum
> 6.12% postgres libc-2.17.so [.] __isinf
> 5.96% postgres postgres [.] float8mul
> 5.33% postgres postgres [.] dsqrt
> 3.90% postgres postgres [.] ftod
> 3.53% postgres postgres [.] Float8GetDatum
> 2.34% postgres postgres [.] DatumGetFloat8
> 2.15% postgres postgres [.] AggCheckCallContext
> 2.03% postgres postgres [.] slot_deform_tuple
> 1.95% postgres libm-2.17.so [.] __sqrt
> 1.19% postgres postgres [.] check_float8_array
>
> HEAD
>
> latency average = 549.071 ms
>
> 31.74% postgres postgres [.] ExecInterpExpr
> 11.02% postgres libc-2.17.so [.] __isinf
> 10.58% postgres postgres [.] float8_accum
> 4.84% postgres postgres [.] check_float8_val
> 4.66% postgres postgres [.] dsqrt
> 3.91% postgres postgres [.] float8mul
> 3.56% postgres postgres [.] ftod
> 3.26% postgres postgres [.] Float8GetDatum
> 2.91% postgres postgres [.] float8_mul
> 2.30% postgres postgres [.] DatumGetFloat8
> 2.19% postgres postgres [.] slot_deform_heap_tuple
> 1.81% postgres postgres [.] AggCheckCallContext
> 1.31% postgres libm-2.17.so [.] __sqrt
> 1.25% postgres postgres [.] check_float8_array
>
> HEAD + patch
>
> latency average = 546.624 ms
>
> 33.51% postgres postgres [.] ExecInterpExpr
> 10.35% postgres postgres [.] float8_accum
> 10.06% postgres libc-2.17.so [.] __isinf
> 4.58% postgres postgres [.] dsqrt
> 4.14% postgres postgres [.] check_float8_val
> 4.03% postgres postgres [.] ftod
> 3.54% postgres postgres [.] float8mul
> 2.96% postgres postgres [.] Float8GetDatum
> 2.38% postgres postgres [.] slot_deform_heap_tuple
> 2.23% postgres postgres [.] DatumGetFloat8
> 2.09% postgres postgres [.] float8_mul
> 1.88% postgres postgres [.] AggCheckCallContext
> 1.65% postgres libm-2.17.so [.] __sqrt
> 1.22% postgres postgres [.] check_float8_array

HEAD + Kuroda-san's patch (compiled with gcc 8)

latency average = 484.604 ms

37.41% postgres postgres [.] ExecInterpExpr
10.83% postgres postgres [.] float8_accum
5.62% postgres postgres [.] dsqrt
4.23% postgres libc-2.17.so [.] __isinf
4.05% postgres postgres [.] float8mul
3.85% postgres postgres [.] ftod
3.18% postgres postgres [.] Float8GetDatum
2.81% postgres postgres [.] slot_deform_heap_tuple
2.63% postgres postgres [.] DatumGetFloat8
2.46% postgres postgres [.] float8_mul
1.91% postgres libm-2.17.so [.] __sqrt

> clang-7 (clang version 7.0.1 (tags/RELEASE_701/final))
> =====
>
> 11.6
>
> latency average = 419.014 ms
>
> 47.57% postgres postgres [.] ExecInterpExpr
> 7.99% postgres postgres [.] float8_accum
> 5.96% postgres postgres [.] dsqrt
> 4.88% postgres postgres [.] float8mul
> 4.23% postgres postgres [.] ftod
> 3.30% postgres postgres [.] slot_deform_tuple
> 3.19% postgres postgres [.] DatumGetFloat8
> 1.92% postgres libm-2.17.so [.] __sqrt
> 1.72% postgres postgres [.] check_float8_array
>
> HEAD
>
> latency average = 452.958 ms
>
> 40.55% postgres postgres [.] ExecInterpExpr
> 10.61% postgres postgres [.] float8_accum
> 4.58% postgres postgres [.] dsqrt
> 3.59% postgres postgres [.] slot_deform_heap_tuple
> 3.54% postgres postgres [.] check_float8_val
> 3.48% postgres postgres [.] ftod
> 3.42% postgres postgres [.] float8mul
> 3.22% postgres postgres [.] DatumGetFloat8
> 2.69% postgres postgres [.] Float8GetDatum
> 2.46% postgres postgres [.] float8_mul
> 2.29% postgres libm-2.17.so [.] __sqrt
> 1.47% postgres postgres [.] check_float8_array
>
> HEAD + patch
>
> latency average = 452.533 ms
>
> 41.05% postgres postgres [.] ExecInterpExpr
> 10.15% postgres postgres [.] float8_accum
> 5.62% postgres postgres [.] dsqrt
> 3.86% postgres postgres [.] check_float8_val
> 3.27% postgres postgres [.] float8mul
> 3.09% postgres postgres [.] slot_deform_heap_tuple
> 2.91% postgres postgres [.] ftod
> 2.88% postgres postgres [.] DatumGetFloat8
> 2.62% postgres postgres [.] float8_mul
> 2.03% postgres libm-2.17.so [.] __sqrt
> 2.00% postgres postgres [.] check_float8_array

HEAD + Kuroda-san's patch (compiled with clang-7)

latency average = 435.454 ms

43.02% postgres postgres [.] ExecInterpExpr
10.86% postgres postgres [.] float8_accum
3.97% postgres postgres [.] dsqrt
3.97% postgres postgres [.] float8mul
3.51% postgres postgres [.] ftod
3.42% postgres postgres [.] slot_deform_heap_tuple
3.36% postgres postgres [.] DatumGetFloat8
1.97% postgres libm-2.17.so [.] __sqrt
1.97% postgres postgres [.] check_float8_array
1.88% postgres postgres [.] float8_mul

Needless to say, that one makes a visible difference, although still
slower compared to PG 11.

Thanks,
Amit