Re: Big Performance drop of Exceptions in UDFs between V11.2 and 13.4

From: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
To: "ldh(at)laurent-hasson(dot)com" <ldh(at)laurent-hasson(dot)com>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Ranier Vilela <ranier(dot)vf(at)gmail(dot)com>, Andrew Dunstan <andrew(at)dunslane(dot)net>, Justin Pryzby <pryzby(at)telsasoft(dot)com>, "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Big Performance drop of Exceptions in UDFs between V11.2 and 13.4
Date: 2021-08-30 02:43:23
Message-ID: CAFj8pRDPew1rg3c-WNxQmUugO0FQRyg3MTy67-qoUtGA=fwZ6Q@mail.gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-performance

Hi

po 30. 8. 2021 v 2:44 odesílatel ldh(at)laurent-hasson(dot)com <
ldh(at)laurent-hasson(dot)com> napsal:

>
>
>
> At this point, I am not sure how to proceed except to rethink that
> toFloat() function and many other places where we use exceptions. We get
> such dirty data that I need a "safe" way to convert a string to float
> without throwing an exception. BTW, I tried other combinations in case
> there may have been some weird interactions with the ::REAL conversion
> operator, but nothing made any change. Could you recommend another approach
> off the top of your head? I could use regexes for testing etc... Or maybe
> there is another option like a no-throw conversion that's built in or in
> some extension that you may know of? Like the "SAFE." Prefix in BigQuery.
>

CREATE OR REPLACE FUNCTION safe_to_double_precision(t text)
RETURNS double precision AS $$
BEGIN
IF $1 SIMILAR TO '[+-]?([0-9]*[.])?[0-9]+' THEN
RETURN $1::double precision;
ELSE
RETURN NULL;
END IF;
END;
$$ LANGUAGE plpgsql IMMUTABLE STRICT;

Regards

Pavel

>
> Thank you,
> Laurent.
>
>
>
>

In response to

Responses

Browse pgsql-performance by date

  From Date Subject
Next Message Justin Pryzby 2021-08-30 03:16:48 Re: Big Performance drop of Exceptions in UDFs between V11.2 and 13.4 (workarounds)
Previous Message Julien Rouhaud 2021-08-30 02:23:08 Re: Big Performance drop of Exceptions in UDFs between V11.2 and 13.4