CREATE TABLE test1 (a int, b text);
CREATE PROCEDURE transaction_test1()
LANGUAGE pltcl
AS $$
for {set i 0} {$i < 10} {incr i} {
    spi_exec "INSERT INTO test1 (a) VALUES ($i)"
    if {$i % 2 == 0} {
        commit
    } else {
        rollback
    }
}
$$;
CALL transaction_test1();
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 pltcl
AS $$
for {set i 0} {$i < 10} {incr i} {
    spi_exec "INSERT INTO test1 (a) VALUES ($i)"
    if {$i % 2 == 0} {
        commit
    } else {
        rollback
    }
}
return 1
$$;
SELECT transaction_test2();
ERROR:  invalid transaction termination
CONTEXT:  while executing
"commit"
    (procedure "__PLTcl_proc_transaction_test2" line 6)
    invoked from within
"__PLTcl_proc_transaction_test2"
in PL/Tcl 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 pltcl
AS $$
spi_exec "CALL transaction_test1()"
return 1
$$;
SELECT transaction_test3();
ERROR:  invalid transaction termination
CONTEXT:  while executing
"commit"
    (procedure "__PLTcl_proc_transaction_test1" line 6)
    invoked from within
"__PLTcl_proc_transaction_test1"
    invoked from within
"spi_exec "CALL transaction_test1()""
    (procedure "__PLTcl_proc_transaction_test3" line 3)
    invoked from within
"__PLTcl_proc_transaction_test3"
in PL/Tcl function transaction_test3()
SELECT * FROM test1;
 a | b 
---+---
(0 rows)

-- commit inside cursor loop
CREATE TABLE test2 (x int);
INSERT INTO test2 VALUES (0), (1), (2), (3), (4);
TRUNCATE test1;
CREATE PROCEDURE transaction_test4a()
LANGUAGE pltcl
AS $$
spi_exec -array row "SELECT * FROM test2 ORDER BY x" {
    spi_exec "INSERT INTO test1 (a) VALUES ($row(x))"
    commit
}
$$;
CALL transaction_test4a();
ERROR:  cannot commit while a subtransaction is active
CONTEXT:  while executing
"commit"
    invoked from within
"spi_exec -array row "SELECT * FROM test2 ORDER BY x" {
    spi_exec "INSERT INTO test1 (a) VALUES ($row(x))"
    commit
}"
    (procedure "__PLTcl_proc_transaction_test4a" line 3)
    invoked from within
"__PLTcl_proc_transaction_test4a"
in PL/Tcl function transaction_test4a()
SELECT * FROM test1;
 a | b 
---+---
(0 rows)

-- rollback inside cursor loop
TRUNCATE test1;
CREATE PROCEDURE transaction_test4b()
LANGUAGE pltcl
AS $$
spi_exec -array row "SELECT * FROM test2 ORDER BY x" {
    spi_exec "INSERT INTO test1 (a) VALUES ($row(x))"
    rollback
}
$$;
CALL transaction_test4b();
ERROR:  cannot roll back while a subtransaction is active
CONTEXT:  while executing
"rollback"
    invoked from within
"spi_exec -array row "SELECT * FROM test2 ORDER BY x" {
    spi_exec "INSERT INTO test1 (a) VALUES ($row(x))"
    rollback
}"
    (procedure "__PLTcl_proc_transaction_test4b" line 3)
    invoked from within
"__PLTcl_proc_transaction_test4b"
in PL/Tcl function transaction_test4b()
SELECT * FROM test1;
 a | b 
---+---
(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);
CREATE PROCEDURE transaction_testfk()
LANGUAGE pltcl
AS $$
# this insert will fail during commit:
spi_exec "INSERT INTO testfk VALUES (0)"
commit
elog WARNING "should not get here"
$$;
CALL transaction_testfk();
ERROR:  insert or update on table "testfk" violates foreign key constraint "testfk_f1_fkey"
CONTEXT:  while executing
"commit"
    (procedure "__PLTcl_proc_transaction_testfk" line 5)
    invoked from within
"__PLTcl_proc_transaction_testfk"
in PL/Tcl function transaction_testfk()
SELECT * FROM testpk;
 id 
----
(0 rows)

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

CREATE OR REPLACE PROCEDURE transaction_testfk()
LANGUAGE pltcl
AS $$
# this insert will fail during commit:
spi_exec "INSERT INTO testfk VALUES (0)"
if [catch {commit} msg] {
    elog INFO $msg
}
# these inserts should work:
spi_exec "INSERT INTO testpk VALUES (1)"
spi_exec "INSERT INTO testfk VALUES (1)"
$$;
CALL transaction_testfk();
INFO:  insert or update on table "testfk" violates foreign key constraint "testfk_f1_fkey"
SELECT * FROM testpk;
 id 
----
  1
(1 row)

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

DROP TABLE test1;
DROP TABLE test2;