From: Tom Lane <tgl@sss.pgh.pa.us>
To: Wells Oliver <wells.oliver@gmail.com>
cc: pgsql-admin@postgresql.org
Subject: Re: Dropping constraints on a table locks referenced table... why?
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Comments: In-reply-to Wells Oliver <wells.oliver@gmail.com>
	message dated "Wed, 18 Apr 2018 11:14:41 -0700"
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Date: Wed, 18 Apr 2018 14:39:25 -0400
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Wells Oliver <wells.oliver@gmail.com> writes:
> Where can I see these triggers? They don't show under the PG Admin trigg=
er
> tab of course, are they, I don't know, special triggers, stored elsewher=
e?
> Can I query an internal PG table?

Sure, like this:

regression=3D# create table pk (f1 int primary key);
CREATE TABLE
regression=3D# create table fk (f1 int references pk);
CREATE TABLE
regression=3D# select tgname,tgfoid::regproc from pg_trigger where tgrelid=
 =3D 'pk'::regclass;
            tgname            |         tgfoid         =

------------------------------+------------------------
 RI_ConstraintTrigger_a_51649 | "RI_FKey_noaction_del"
 RI_ConstraintTrigger_a_51650 | "RI_FKey_noaction_upd"
(2 rows)

regression=3D# select tgname,tgfoid::regproc from pg_trigger where tgrelid=
 =3D 'fk'::regclass;
            tgname            |       tgfoid        =

------------------------------+---------------------
 RI_ConstraintTrigger_c_51651 | "RI_FKey_check_ins"
 RI_ConstraintTrigger_c_51652 | "RI_FKey_check_upd"
(2 rows)

psql and probably most other client tools hide these triggers figuring
they're uninteresting, but they're pretty ordinary triggers otherwise.

			regards, tom lane