From: Tom Lane <tgl@sss.pgh.pa.us>
To: Bruce Momjian <bruce@momjian.us>
cc: Thomas Munro <thomas.munro@enterprisedb.com>, ian@thepathcentral.com,
        pgsql-docs@postgresql.org, Andrew Gierth <andrew@tao11.riddles.org.uk>
Subject: Re: Trigger behaviour not as stated
In-reply-to: <20180128203402.GB4380@momjian.us>
References: <20171129193934.27108.30796@wrigleys.postgresql.org>
 <20180124181008.GK17109@momjian.us> <20180124220701.GP17109@momjian.us>
 <CAEepm=1cAO8y4dFv_xd=43iP7f4T3A2hYAzjgjQagHtt7H87Fw@mail.gmail.com>
 <28238.1517167118@sss.pgh.pa.us> <20180128203402.GB4380@momjian.us>
Comments: In-reply-to Bruce Momjian <bruce@momjian.us>
	message dated "Sun, 28 Jan 2018 15:34:02 -0500"
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Date: Sun, 28 Jan 2018 15:57:07 -0500
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Bruce Momjian <bruce@momjian.us> writes:
> Uh, I don't think we want to highlight the statement vs row difference
> here but the fact that statement triggers fire on the referenced object
> and not on the effected rows.  I have attached an updated patch which I
> think is an improvement

     statement-level triggers for its partitions or child tables.  In cont=
rast,
!    row-level triggers are fired on the rows in effected partitions or
!    child tables, even if they are not referenced in the query.

I still think that that's not well written.  A large part of the confusion
here is over what "referenced" means.  To my mind, child tables/partitions
are referenced by an inherited query, just not explicitly.  So that's why
I'd prefer wording like "directly named in the query" (or "explicitly
named").  If you insist on using "referenced" you could write "explicitly
referenced", but IMO that's longer and no clearer.

A lesser complaint is that this reads like the antecedent of "they" is the
rows, not the tables containing them, making the meaning of "referenced"
even less clear.

Maybe something like

    In contrast, row-level triggers are fired for individual row change
    events, and the triggers that are fired for an event are those
    attached to the specific table containing the changed row, even if
    it is a partition or child table not directly named in the query.

			regards, tom lane