> -----Original Message-----
> From: Tom Lane <tgl@xxxxxxxxxxxxx>
> Sent: Friday, August 27, 2021 13:43
> To: ldh@xxxxxxxxxxxxxxxxxx
> Cc: Justin Pryzby <pryzby@xxxxxxxxxxxxx>; Ranier Vilela
> <ranier.vf@xxxxxxxxx>; pgsql-performance@xxxxxxxxxxxxxx
> Subject: Re: Big Performance drop of Exceptions in UDFs between V11.2
> and 13.4
>
> "ldh@xxxxxxxxxxxxxxxxxx" <ldh@xxxxxxxxxxxxxxxxxx> writes:
> > That being said, do you have any suggestion how I could circumvent
> the
> > issue altogether?
>
> Based on Andrew's report, it seems like you might be able to work
> around it for the time being by disabling message translations, i.e.
> SET lc_messages = 'C';
> Even if that's not acceptable in your work environment, it would be
> useful to verify that you see an improvement from it.
>
> regards, tom lane
Hello Tom.... hit the send button accidentally.
SET lc_messages = 'C';
drop table sampletest;
create table sampletest (a varchar, b varchar);
insert into sampletest (a, b)
select substr(md5(random()::text), 0, 15), (100000000*random())::integer::varchar
from generate_series(1,100000);
CREATE OR REPLACE FUNCTION toFloat(str varchar, val real)
RETURNS real AS $$
BEGIN
RETURN case when str is null then val else str::real end;
EXCEPTION WHEN OTHERS THEN
RETURN val;
END;
$$ LANGUAGE plpgsql COST 1 IMMUTABLE;
show lc_messages; --> OK 'C'
explain (analyze,buffers,COSTS,TIMING)
select MAX(toFloat(b, null)) as "b" from sampletest
Aggregate (cost=2137.00..2137.01 rows=1 width=4) (actual time=175.551..175.552 rows=1 loops=1)
Buffers: shared hit=637
-> Seq Scan on sampletest (cost=0.00..1637.00 rows=100000 width=8) (actual time=0.014..9.270 rows=100000 loops=1)
Buffers: shared hit=637
Planning Time: 0.087 ms
Execution Time: 175.600 ms
explain (analyze,buffers,COSTS,TIMING)
select MAX(toFloat(a, null)) as "a" from sampletest
Aggregate (cost=2137.00..2137.01 rows=1 width=4) (actual time=88031.549..88031.551 rows=1 loops=1)
Buffers: shared hit=637
-> Seq Scan on sampletest (cost=0.00..1637.00 rows=100000 width=15) (actual time=0.008..34.494 rows=100000 loops=1)
Buffers: shared hit=637
Planning:
Buffers: shared hit=4
Planning Time: 0.171 ms
Execution Time: 88031.585 ms
Doesn't seem to make a difference unless I misunderstood what you were asking for regarding the locale?
Thank you,
Laurent.
