Hi, I've read the documentation, that's why I said this might be undocumented. Try the SQL in Postgres 11 and see that it works for yourself. I have an analogous trigger in production from yesterday and I've tested it in local environment as well.
On Fri, Jan 4, 2019 at 12:56 PM Charles Clavadetscher < clavadetsc...@swisspug.org> wrote: > Hello > > > > *From:* Kristjan Tammekivi <kristjantammek...@gmail.com> > *Sent:* Freitag, 4. Januar 2019 11:46 > *To:* pgsql-gene...@postgresql.org > *Subject:* Potentially undocumented behaviour change in Postgres 11 > concerning OLD record in an after insert trigger > > > > Hi, > > > > I've noticed a change in the behaviour in triggers / hstores in Postgres > 11.1 when compared to Postgres 10.5. > > The following won't work on Postgres 10.5 but in Postgres 11.1 it works > just fine: > > > > CREATE EXTENSION hstore; > > CREATE TABLE _tmp_test1 (id serial PRIMARY KEY, val INTEGER); > CREATE TABLE _tmp_test1_changes (id INTEGER, changes HSTORE); > > CREATE FUNCTION test1_trigger () > RETURNS TRIGGER > LANGUAGE plpgsql > AS > $BODY$ > BEGIN > INSERT INTO _tmp_test1_changes (id, changes) VALUES (NEW.id, hstore(OLD) - > hstore(NEW)); > RETURN NEW; > END > $BODY$; > > CREATE TRIGGER table_update AFTER INSERT OR UPDATE ON _tmp_test1 > FOR EACH ROW EXECUTE PROCEDURE test1_trigger(); > > > > INSERT INTO _tmp_test1 (val) VALUES (5); > > ERROR: record "old" is not assigned yet > > DETAIL: The tuple structure of a not-yet-assigned record is indeterminate. > > CONTEXT: SQL statement "INSERT INTO _tmp_test1_changes (id, changes) > VALUES (NEW.id, hstore(OLD) - hstore(NEW))" > > PL/pgSQL function test1_trigger() line 3 at SQL statement > > > > I couldn't find anything about this in the release notes ( > https://www.postgresql.org/docs/11/release-11.html), but maybe I just > didn't know what to look for. > > > > *I doubt that this works on any PG version for INSERT.* > > > > *According to the documentation:* > > > > *https://www.postgresql.org/docs/10/plpgsql-trigger.html > <https://www.postgresql.org/docs/10/plpgsql-trigger.html> and > https://www.postgresql.org/docs/11/plpgsql-trigger.html > <https://www.postgresql.org/docs/11/plpgsql-trigger.html>* > > > > *OLD: **Data type **RECORD**; variable holding the old database row for * > *UPDATE**/**DELETE** operations in row-level triggers. This variable is > unassigned in statement-level triggers and for **INSERT** operations.* > > > > *Regards* > > *Charles* >
