# ALTER TABLE - Add and remove inheritance with concurrent reads

setup
{
 CREATE TABLE p (a integer);
 INSERT INTO p VALUES(1);
 CREATE TABLE c1 () INHERITS (p);
 INSERT INTO c1 VALUES(10);
 CREATE TABLE c2 (a integer);
 INSERT INTO c2 VALUES(100);
}

teardown
{
 DROP TABLE IF EXISTS c1, c2, p;
}

session "s1"
step "s1b"	{ BEGIN; }
step "s1delc1"	{ ALTER TABLE c1 NO INHERIT p; }
step "s1modc1a"	{ ALTER TABLE c1 ALTER COLUMN a TYPE float; }
step "s1addc2"	{ ALTER TABLE c2 INHERIT p; }
step "s1dropc1"	{ DROP TABLE c1; }
step "s1c"	{ COMMIT; }

session "s2"
step "s2sel"	{ SELECT SUM(a) FROM p; }

# NO INHERIT will not be visible to concurrent select,
# since we identify children before locking them
permutation "s1b" "s1delc1" "s2sel" "s1c" "s2sel"
# adding inheritance likewise is not seen if s1 commits after s2 locks p
permutation "s1b" "s1delc1" "s1addc2" "s2sel" "s1c" "s2sel"
# but we do cope with DROP on a child table
permutation "s1b" "s1dropc1" "s2sel" "s1c" "s2sel"
# this case currently results in an error; doesn't seem worth preventing
permutation "s1b" "s1delc1" "s1modc1a" "s2sel" "s1c" "s2sel"