--
-- Commit Timestamp
--
SHOW track_commit_timestamp;
 track_commit_timestamp 
------------------------
 off
(1 row)

CREATE TABLE committs_test(id serial, ts timestamptz default now());
INSERT INTO committs_test DEFAULT VALUES;
INSERT INTO committs_test DEFAULT VALUES;
INSERT INTO committs_test DEFAULT VALUES;
SELECT id,
       pg_xact_commit_timestamp(xmin) >= ts,
       pg_xact_commit_timestamp(xmin) <= now(),
       pg_xact_commit_timestamp(xmin) - ts < '60s' -- 60s should give a lot of reserve
FROM committs_test
ORDER BY id;
ERROR:  could not get commit timestamp data
HINT:  Make sure the configuration parameter "track_commit_timestamp" is set.
DROP TABLE committs_test;
SELECT pg_xact_commit_timestamp('0'::xid);
ERROR:  cannot retrieve commit timestamp for transaction 0
SELECT pg_xact_commit_timestamp('1'::xid);
ERROR:  cannot retrieve commit timestamp for transaction 1
SELECT pg_xact_commit_timestamp('2'::xid);
ERROR:  cannot retrieve commit timestamp for transaction 2
SELECT x.xid::text::bigint > 0, x.timestamp > '-infinity'::timestamptz, x.timestamp <= now() FROM pg_last_committed_xact() x;
ERROR:  could not get commit timestamp data
HINT:  Make sure the configuration parameter "track_commit_timestamp" is set.