Do not let the system to do extra work. Logging changes with a BEFORE trigger means extra work for rolling back the changes in case the logged data modification fails.
Notes
The Tr subquery has been created based on the subquery of INFORMATION_SCHEMA.triggers view. In the returned body of routine the query replaces each newline character with the line break (br) tag for the better readability in case the query result is displayed in a web browser. It could be that the trigger function contains INSERT INTO statement for another purposes than logging.
Type
Problem detection (Each row in the result could represent a flaw in the design)
WITH Tr AS (SELECT
n.nspname AS trigger_schema,
t.tgname AS trigger_name,
em.text AS event_manipulation,
c.relname AS trigger_table,
np.nspname AS routine_schema,
p.proname AS routine_name,
p.prosrc AS routine_definition,
(SELECT DISTINCT action_condition FROM INFORMATION_SCHEMA.triggers AS it WHERE it.trigger_schema=n.nspname AND it.event_object_table=c.relname AND it.trigger_name=t.tgname) AS action_condition,
CASE t.tgtype::integer & 1
WHEN 1 THEN 'ROW'
ELSE 'STATEMENT'
END AS action_orientation,
CASE t.tgtype::integer & 66
WHEN 2 THEN 'BEFORE'
WHEN 64 THEN 'INSTEAD OF'
ELSE 'AFTER'
END AS action_timing
FROM pg_namespace n,
pg_class c,
pg_trigger t,
pg_proc p,
pg_namespace np,
( VALUES (4,'INSERT'), (8,'DELETE'), (16,'UPDATE'), (32,'TRUNCATE')) em(num, text)
WHERE n.oid = c.relnamespace
AND c.oid = t.tgrelid
AND t.tgfoid=p.oid
AND p.pronamespace=np.oid
AND (t.tgtype::integer & em.num) <> 0
AND NOT t.tgisinternal
AND NOT pg_is_other_temp_schema(n.oid))
SELECT trigger_schema, trigger_table, action_timing, event_manipulation, action_orientation, action_condition, routine_name, regexp_replace(routine_definition,'[\r\n]',' ','g') AS routine_definition
FROM Tr
WHERE action_timing='BEFORE' AND routine_definition~* 'INSERT[[:space:]]+INTO'
ORDER BY trigger_schema, trigger_table, routine_name;
Collections
This query belongs to the following collections:
Name
Description
Find problems automatically
Queries, that results point to problems in the database. Each query in the collection produces an initial assessment. However, a human reviewer has the final say as to whether there is a problem or not .
Categories
This query is classified under the following categories:
Name
Description
Performance
Queries of this category provide information about indexes in a database.
Triggers and rules
Queries of this category provide information about triggers and rules in a database.