\set VERBOSITY terse
-- predictability
SET synchronous_commit = on;
DROP TABLE IF EXISTS tbl;
CREATE TABLE tbl (id int);
SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot', 'wal2json');
 ?column? 
----------
 init
(1 row)

-- One row should have one record and one nextlsn
INSERT INTO tbl VALUES (1);
SELECT count(*) = 1, count(distinct ((data::json)->'nextlsn')::text) = 1 FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'format-version', '1', 'include-lsn', '1');
 ?column? | ?column? 
----------+----------
 t        | t
(1 row)

-- Two rows should have two records and two nextlsns
INSERT INTO tbl VALUES (2);
INSERT INTO tbl VALUES (3);
SELECT count(*) = 2, count(distinct ((data::json)->'nextlsn')::text) = 2 FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'format-version', '1', 'include-lsn', '1');
 ?column? | ?column? 
----------+----------
 t        | t
(1 row)

-- Two rows in one transaction should have one record and one nextlsn
INSERT INTO tbl VALUES (4), (5);
SELECT count(*) = 1, count(distinct ((data::json)->'nextlsn')::text) = 1 FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'format-version', '1', 'include-lsn', '1');
 ?column? | ?column? 
----------+----------
 t        | t
(1 row)

SELECT 'stop' FROM pg_drop_replication_slot('regression_slot');
 ?column? 
----------
 stop
(1 row)

