ddl_command_end not firing DROP events

[Demitri Muna]

Hi,

I’ve created a trigger where I want to capture schema-changing events. I’m 
finding that DROP events are not being triggered when using “ddl_command_end". 
The test case below demonstrates this. I am running PostgreSQL 10.4. The 
trigger is fired for the CREATE event, but not DROP TYPE or DROP TABLE.

I came across the same question on the mailing list, but the solution was to 
use the “sql_drop” trigger instead.

https://www.postgresql.org/message-id/CAHE3wgjX-N%3DX9mccp4Bs-y-%3DHE%3DqayHEpXpCs1jMT%3DW0ZsYc5A%40mail.gmail.com

The documentation suggests that one should be able to use “ddl_command_end” 
instead of creating two triggers (i.e. one for DROPs, another for everything 
else).

Test:

CREATE FUNCTION test_event_trigger_for_drops()
        RETURNS event_trigger LANGUAGE plpgsql AS $$
DECLARE
    obj record;
BEGIN
    FOR obj IN SELECT * FROM pg_event_trigger_ddl_commands()
    LOOP
        RAISE NOTICE 'caught % event on ''%''',
                     obj.command_tag,
                     obj.object_identity;
    END LOOP;
END
$$;
CREATE EVENT TRIGGER test_event_trigger_for_drops
   ON ddl_command_end
   EXECUTE PROCEDURE test_event_trigger_for_drops();

CREATE TYPE foo AS (f1 int, f2 text);
DROP TYPE foo;
CREATE TABLE drop_test ( pk int ) WITH ( OIDS = FALSE );
DROP TABLE drop_test;

-- for ease of copy/paste to delete the above
DROP EVENT TRIGGER test_event_trigger_for_drops;
DROP FUNCTION test_event_trigger_for_drops;

Cheers,
Demitri