Hi,
In <[email protected]>
"Re: Make COPY format extendable: Extract COPY TO format implementations" on
Thu, 22 Feb 2024 18:39:48 +0900 (JST),
Sutou Kouhei <[email protected]> wrote:
> How about adding "is_csv" to CopyReadline() and
> CopyReadLineText() too?
I tried this on my environment. This is a change for COPY
FROM not COPY TO but this decreases COPY TO
performance with [1]... Hmm...
master: 697.693 msec (the best case)
v15: 576.374 msec (the best case)
v15+this: 593.559 msec (the best case)
[1] COPY (SELECT
1::int2,2::int2,3::int2,4::int2,5::int2,6::int2,7::int2,8::int2,9::int2,10::int2,11::int2,12::int2,13::int2,14::int2,15::int2,16::int2,17::int2,18::int2,19::int2,20::int2,
generate_series(1, 1000000::int4)) TO '/dev/null' \watch c=15
So I think that v15 is good.
perf result of master:
# Children Self Command Shared Object Symbol
# ........ ........ ........ .................
.........................................
#
31.39% 14.54% postgres postgres [.] CopyOneRowTo
|--17.00%--CopyOneRowTo
| |--10.61%--FunctionCall1Coll
| | --8.40%--int2out
| | |--2.58%--pg_ltoa
| | | --0.68%--pg_ultoa_n
| | |--1.11%--pg_ultoa_n
| | |--0.83%--AllocSetAlloc
| |
|--0.69%--__memcpy_avx_unaligned_erms (inlined)
| | |--0.58%--FunctionCall1Coll
| | --0.55%--memcpy@plt
| |--3.25%--appendBinaryStringInfo
| | --0.56%--pg_ultoa_n
| --0.69%--CopyAttributeOutText
perf result of v15:
# Children Self Command Shared Object Symbol
# ........ ........ ........ .................
.........................................
#
25.60% 10.47% postgres postgres [.] CopyToTextOneRow
|--15.39%--CopyToTextOneRow
| |--10.44%--FunctionCall1Coll
| | |--7.25%--int2out
| | | |--2.60%--pg_ltoa
| | | | --0.71%--pg_ultoa_n
| | | |--0.90%--FunctionCall1Coll
| | | |--0.84%--pg_ultoa_n
| | | --0.66%--AllocSetAlloc
| | |--0.79%--ExecProjectSet
| | --0.68%--int4out
| |--2.50%--appendBinaryStringInfo
| --0.53%--CopyAttributeOutText
The profiles on Michael's environment [2] showed that
CopyOneRow() % was increased by v15. But it
(CopyToTextOneRow() % not CopyOneRow() %) wasn't increased
by v15. It's decreased instead.
[2]
https://www.postgresql.org/message-id/flat/ZdbtQJ-p5H1_EDwE%40paquier.xyz#6439e6ad574f2d47cd7220e9bfed3889
So I think that v15 doesn't have performance regression but
my environment isn't suitable for benchmark...
Thanks,
--
kou
