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From: Thomas Munro <thomas.munro@enterprisedb.com>
Date: Sun, 28 Jan 2018 23:19:47 +1300
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 <CAEepm=1cAO8y4dFv_xd=43iP7f4T3A2hYAzjgjQagHtt7H87Fw@mail.gmail.com>
Subject: Re: Trigger behaviour not as stated
To: Bruce Momjian <bruce@momjian.us>
Cc: ian@thepathcentral.com, pgsql-docs@postgresql.org,
	Andrew Gierth <andrew@tao11.riddles.org.uk>
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On Thu, Jan 25, 2018 at 11:07 AM, Bruce Momjian <bruce@momjian.us> wrote:
> On Wed, Jan 24, 2018 at 01:10:08PM -0500, Bruce Momjian wrote:
>> On Wed, Nov 29, 2017 at 07:39:34PM +0000, ian@thepathcentral.com wrote:
>> > The following documentation comment has been logged on the website:
>> >
>> > Page: https://www.postgresql.org/docs/10/static/sql-createtrigger.html
>> > Description:
>> >
>> > URL: https://www.postgresql.org/docs/current/static/sql-createtrigger.html
>> >
>> > Statement: &quot;In contrast, row-level triggers are fired for all affected
>> > partitions or child tables.&quot;
>> >
>> > Row-level triggers are not fired on child tables where the trigger ON BEFORE
>> > UPDATE | DELETE is on the parent table. Only works on BEFORE INSERT.
>
> OK, I have some more details on this.  First there is the Stackoverflow
> report:
>
>   https://stackoverflow.com/questions/47557665/postgresql-on-before-delete-trigger-not-firing-on-a-parent-table-in-an-inheritan
>
> The report confirms that row-level triggers are fired _only_ on affected
> tables (meaning the table that had a row change), not on any table
> mentioned _or_ affected.  The current wording, added in this commit:
>
>         commit 501ed02cf6f4f60c3357775eb07578aebc912d3a
>         Author: Andrew Gierth <rhodiumtoad@postgresql.org>
>         Date:   Wed Jun 28 18:55:03 2017 +0100
>
>             Fix transition tables for partition/inheritance.
>
>             We disallow row-level triggers with transition tables on child tables.
>             Transition tables for triggers on the parent table contain only those
>             columns present in the parent.  (We can't mix tuple formats in a
>             single transition table.)
>
>             Patch by Thomas Munro
>
>             Discussion: https://postgr.es/m/CA%2BTgmoZzTBBAsEUh4MazAN7ga%3D8SsMC-Knp-6cetts9yNZUCcg%40mail.gmail.com
>
> should be improved.  The attached patch updates the docs to say
> statement-level triggers fire on the "referenced" table, while row-level
> triggers fire only on the "affected" table, (vs. all affected tables)
> even if they are not referenced in the query.  I would backpatch this to
> PG 10.

+1

I was trying to convey that, but it does seem a little terse and
cryptic.  Your addition of "referenced" and "only" make it clearer.

-- 
Thomas Munro
http://www.enterprisedb.com