CREATE TABLE test1 (a int, b text);
CREATE PROCEDURE transaction_test1()
LANGUAGE plpython3u
AS $$
for i in range(0, 10):
    plpy.execute("INSERT INTO test1 (a) VALUES (%d)" % i)
    if i % 2 == 0:
        plpy.commit()
    else:
        plpy.rollback()
$$;
CALL transaction_test1();
SELECT * FROM test1;
 a | b 
---+---
 0 | 
 2 | 
 4 | 
 6 | 
 8 | 
(5 rows)

TRUNCATE test1;
DO
LANGUAGE plpython3u
$$
for i in range(0, 10):
    plpy.execute("INSERT INTO test1 (a) VALUES (%d)" % i)
    if i % 2 == 0:
        plpy.commit()
    else:
        plpy.rollback()
$$;
SELECT * FROM test1;
 a | b 
---+---
 0 | 
 2 | 
 4 | 
 6 | 
 8 | 
(5 rows)

TRUNCATE test1;
-- not allowed in a function
CREATE FUNCTION transaction_test2() RETURNS int
LANGUAGE plpython3u
AS $$
for i in range(0, 10):
    plpy.execute("INSERT INTO test1 (a) VALUES (%d)" % i)
    if i % 2 == 0:
        plpy.commit()
    else:
        plpy.rollback()
return 1
$$;
SELECT transaction_test2();
ERROR:  spiexceptions.InvalidTransactionTermination: invalid transaction termination
CONTEXT:  Traceback (most recent call last):
  PL/Python function "transaction_test2", line 5, in <module>
    plpy.commit()
PL/Python function "transaction_test2"
SELECT * FROM test1;
 a | b 
---+---
(0 rows)

-- also not allowed if procedure is called from a function
CREATE FUNCTION transaction_test3() RETURNS int
LANGUAGE plpython3u
AS $$
plpy.execute("CALL transaction_test1()")
return 1
$$;
SELECT transaction_test3();
ERROR:  spiexceptions.InvalidTransactionTermination: spiexceptions.InvalidTransactionTermination: invalid transaction termination
CONTEXT:  Traceback (most recent call last):
  PL/Python function "transaction_test3", line 2, in <module>
    plpy.execute("CALL transaction_test1()")
PL/Python function "transaction_test3"
SELECT * FROM test1;
 a | b 
---+---
(0 rows)

-- DO block inside function
CREATE FUNCTION transaction_test4() RETURNS int
LANGUAGE plpython3u
AS $$
plpy.execute("DO LANGUAGE plpython3u $x$ plpy.commit() $x$")
return 1
$$;
SELECT transaction_test4();
ERROR:  spiexceptions.InvalidTransactionTermination: spiexceptions.InvalidTransactionTermination: invalid transaction termination
CONTEXT:  Traceback (most recent call last):
  PL/Python function "transaction_test4", line 2, in <module>
    plpy.execute("DO LANGUAGE plpython3u $x$ plpy.commit() $x$")
PL/Python function "transaction_test4"
-- commit inside subtransaction (prohibited)
DO LANGUAGE plpython3u $$
s = plpy.subtransaction()
s.enter()
plpy.commit()
$$;
WARNING:  forcibly aborting a subtransaction that has not been exited
ERROR:  spiexceptions.InvalidTransactionTermination: cannot commit while a subtransaction is active
CONTEXT:  Traceback (most recent call last):
  PL/Python anonymous code block, line 4, in <module>
    plpy.commit()
PL/Python anonymous code block
-- commit inside cursor loop
CREATE TABLE test2 (x int);
INSERT INTO test2 VALUES (0), (1), (2), (3), (4);
TRUNCATE test1;
DO LANGUAGE plpython3u $$
for row in plpy.cursor("SELECT * FROM test2 ORDER BY x"):
    plpy.execute("INSERT INTO test1 (a) VALUES (%s)" % row['x'])
    plpy.commit()
$$;
SELECT * FROM test1;
 a | b 
---+---
 0 | 
 1 | 
 2 | 
 3 | 
 4 | 
(5 rows)

-- check that this doesn't leak a holdable portal
SELECT * FROM pg_cursors;
 name | statement | is_holdable | is_binary | is_scrollable | creation_time 
------+-----------+-------------+-----------+---------------+---------------
(0 rows)

-- error in cursor loop with commit
TRUNCATE test1;
DO LANGUAGE plpython3u $$
for row in plpy.cursor("SELECT * FROM test2 ORDER BY x"):
    plpy.execute("INSERT INTO test1 (a) VALUES (12/(%s-2))" % row['x'])
    plpy.commit()
$$;
ERROR:  spiexceptions.DivisionByZero: division by zero
CONTEXT:  Traceback (most recent call last):
  PL/Python anonymous code block, line 3, in <module>
    plpy.execute("INSERT INTO test1 (a) VALUES (12/(%s-2))" % row['x'])
PL/Python anonymous code block
SELECT * FROM test1;
  a  | b 
-----+---
  -6 | 
 -12 | 
(2 rows)

SELECT * FROM pg_cursors;
 name | statement | is_holdable | is_binary | is_scrollable | creation_time 
------+-----------+-------------+-----------+---------------+---------------
(0 rows)

-- rollback inside cursor loop
TRUNCATE test1;
DO LANGUAGE plpython3u $$
for row in plpy.cursor("SELECT * FROM test2 ORDER BY x"):
    plpy.execute("INSERT INTO test1 (a) VALUES (%s)" % row['x'])
    plpy.rollback()
$$;
SELECT * FROM test1;
 a | b 
---+---
(0 rows)

SELECT * FROM pg_cursors;
 name | statement | is_holdable | is_binary | is_scrollable | creation_time 
------+-----------+-------------+-----------+---------------+---------------
(0 rows)

-- first commit then rollback inside cursor loop
TRUNCATE test1;
DO LANGUAGE plpython3u $$
for row in plpy.cursor("SELECT * FROM test2 ORDER BY x"):
    plpy.execute("INSERT INTO test1 (a) VALUES (%s)" % row['x'])
    if row['x'] % 2 == 0:
        plpy.commit()
    else:
        plpy.rollback()
$$;
SELECT * FROM test1;
 a | b 
---+---
 0 | 
 2 | 
 4 | 
(3 rows)

SELECT * FROM pg_cursors;
 name | statement | is_holdable | is_binary | is_scrollable | creation_time 
------+-----------+-------------+-----------+---------------+---------------
(0 rows)

-- check handling of an error during COMMIT
CREATE TABLE testpk (id int PRIMARY KEY);
CREATE TABLE testfk(f1 int REFERENCES testpk DEFERRABLE INITIALLY DEFERRED);
DO LANGUAGE plpython3u $$
# this insert will fail during commit:
plpy.execute("INSERT INTO testfk VALUES (0)")
plpy.commit()
plpy.warning('should not get here')
$$;
ERROR:  spiexceptions.ForeignKeyViolation: insert or update on table "testfk" violates foreign key constraint "testfk_f1_fkey"
DETAIL:  Key (f1)=(0) is not present in table "testpk".
CONTEXT:  Traceback (most recent call last):
  PL/Python anonymous code block, line 4, in <module>
    plpy.commit()
PL/Python anonymous code block
SELECT * FROM testpk;
 id 
----
(0 rows)

SELECT * FROM testfk;
 f1 
----
(0 rows)

DO LANGUAGE plpython3u $$
# this insert will fail during commit:
plpy.execute("INSERT INTO testfk VALUES (0)")
try:
    plpy.commit()
except Exception as e:
    plpy.info('sqlstate: %s' % (e.sqlstate))
# these inserts should work:
plpy.execute("INSERT INTO testpk VALUES (1)")
plpy.execute("INSERT INTO testfk VALUES (1)")
$$;
INFO:  sqlstate: 23503
SELECT * FROM testpk;
 id 
----
  1
(1 row)

SELECT * FROM testfk;
 f1 
----
  1
(1 row)

DROP TABLE test1;
DROP TABLE test2;