From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Arne Roland <A.Roland@index.de>
Cc: vignesh C <vignesh21@gmail.com>
Cc: Zhihong Yu <zyu@yugabyte.com>
Cc: Pg Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: Rename of triggers for partitioned tables
Date: Mon, 26 Jul 2021 13:14:20 -0400
Message-ID: <202107261714.kuzrvstzrufh@alvherre.pgsql> (raw)
In-Reply-To: <1337562.1627224583@sss.pgh.pa.us>
On 2021-Jul-25, Tom Lane wrote:
> Perhaps there's no actual bug there, but it's still horrible coding.
> For one thing, the implication that found could be negative is extremely
> confusing to readers. A boolean might be better. However, I wonder why
> you bothered with a flag in the first place. The usual convention if
> we know there can be only one match is to just not write a loop at all,
> with a suitable comment, like this pre-existing example elsewhere in
> trigger.c:
>
> /* There should be at most one matching tuple */
> if (HeapTupleIsValid(tuple = systable_getnext(tgscan)))
>
> If you're not quite convinced there can be only one match, then it
> still shouldn't be an Assert --- a real test-and-elog would be better.
I agree that coding there was dubious. I've removed the flag and assert.
Arne complained that there should be a unique constraint on (tgrelid,
tgparentid) which would sidestep the need for this to be a loop. I
don't think it's really necessary, and I'm not sure how to create a
system index WHERE tgparentid <> 0.
--
Álvaro Herrera 39°49'30"S 73°17'W — https://www.EnterpriseDB.com/
"Saca el libro que tu religión considere como el indicado para encontrar la
oración que traiga paz a tu alma. Luego rebootea el computador
y ve si funciona" (Carlos Duclós)
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To: pgsql-hackers@postgresql.org
Cc: alvherre@alvh.no-ip.org, tgl@sss.pgh.pa.us, A.Roland@index.de, vignesh21@gmail.com, zyu@yugabyte.com, pgsql-hackers@lists.postgresql.org
Subject: Re: Rename of triggers for partitioned tables
In-Reply-To: <202107261714.kuzrvstzrufh@alvherre.pgsql>
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