Message-ID: <3850a85012d040827b10193189edbe2c23a64f8f.camel@cybertec.at>
Subject: Re: proposal: schema variables
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Pavel Stehule <pavel.stehule@gmail.com>
Cc: Erik Rijkers <er@xs4all.nl>, Michael Paquier <michael@paquier.xyz>, Amit
 Kapila <amit.kapila16@gmail.com>, DUVAL REMI <REMI.DUVAL@cheops.fr>,
 PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: Mon, 02 Sep 2024 16:00:51 +0200
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On Thu, 2024-08-29 at 19:33 +0200, Pavel Stehule wrote:
> > > > > =C2=A0 > +=C2=A0 =C2=A0/*
> > > > > =C2=A0 > +=C2=A0 =C2=A0 * Although svar is freshly validated in t=
his point, the svar->is_valid can
> > > > > =C2=A0 > +=C2=A0 =C2=A0 * be false, due possible accepting invali=
dation message inside domain
> > > > > =C2=A0 > +=C2=A0 =C2=A0 * check. Now, the validation is done afte=
r lock, that can also accept
> > > > > =C2=A0 > +=C2=A0 =C2=A0 * invalidation message, so validation sho=
uld be trustful.
> > > > > =C2=A0 > +=C2=A0 =C2=A0 *
> > > > > =C2=A0 > +=C2=A0 =C2=A0 * For now, we don't need to repeat valida=
tion. Only svar should be valid
> > > > > =C2=A0 > +=C2=A0 =C2=A0 * pointer.
> > > > > =C2=A0 > +=C2=A0 =C2=A0 */
> > > >=20
> > > > This comment is related to assertions. Before I had there `Assert(s=
var->is_valid)`,
> > > > because I expected it. But it was not always true. And although it =
is true,
> > > > we don't need to validate a variable, because at this moment, the v=
ariable
> > > > should be locked, and then we can return content safely.
> > >=20
> > > I guess my main problem is the word "trustful".=C2=A0 I don't recogni=
ze that word.
> > > Perhaps you can reword the comment along the lines of your above expl=
anation.
> >=20
> >=20
> > I'll try to change it
>=20
> is this better
>=20
> <-->/*
> <--> * Although svar is freshly validated in this point, the svar->is_val=
id can
> <--> * be false, due possible accepting invalidation message inside domai=
n
> <--> * check. But now, the variable, and all dependencies are locked, so =
we
> <--> * don't need to repeat validation.
> <--> */

Much better.

Here is an improved version:

  Although "svar" is freshly validated in this point, svar->is_valid can
  be false, if an invalidation message ws processed during the domain check=
.
  But the variable and all its dependencies are locked now, so we don't nee=
d
  to repeat the validation.

Yours,
Laurenz Albe