Parsed test spec with 3 sessions

starting permutation: s2txid s1init s3txid s2alter s2c s1insert s1checkpoint s1start s1insert s1alter s1insert s1start
step s2txid: BEGIN ISOLATION LEVEL REPEATABLE READ; SELECT txid_current() IS NULL;
?column?       

f              
step s1init: SELECT 'init' FROM pg_create_logical_replication_slot('isolation_slot', 'test_decoding'); <waiting ...>
step s3txid: BEGIN ISOLATION LEVEL REPEATABLE READ; SELECT txid_current() IS NULL;
?column?       

f              
step s2alter: ALTER TABLE do_write ADD COLUMN addedbys2 int;
step s2c: COMMIT;
step s1init: <... completed>
?column?       

init           
step s1insert: INSERT INTO do_write DEFAULT VALUES;
step s1checkpoint: CHECKPOINT;
step s1start: SELECT data FROM pg_logical_slot_get_changes('isolation_slot', NULL, NULL, 'include-xids', 'false');
data           

BEGIN          
table public.do_write: INSERT: id[integer]:1 addedbys2[integer]:null
COMMIT         
step s1insert: INSERT INTO do_write DEFAULT VALUES;
step s1alter: ALTER TABLE do_write ADD COLUMN addedbys1 int;
step s1insert: INSERT INTO do_write DEFAULT VALUES;
step s1start: SELECT data FROM pg_logical_slot_get_changes('isolation_slot', NULL, NULL, 'include-xids', 'false');
data           

BEGIN          
table public.do_write: INSERT: id[integer]:2 addedbys2[integer]:null
COMMIT         
BEGIN          
COMMIT         
BEGIN          
table public.do_write: INSERT: id[integer]:3 addedbys2[integer]:null addedbys1[integer]:null
COMMIT         
?column?       

stop