how to use SAVEPOINT in stored function

[Frank.Motzkat@xxxxxxx]

Hi community,

I would like using savepoints in my
stored functions but I always get the error

ERROR:  SPI_execute_plan
failed executing query "SAVEPOINT my_savepoint": SPI_ERROR_TRANSACTION
CONTEXT:  PL/pgSQL function
"savepoint_test" line 3 at SQL statement

My test function can be found below.
I would be very grateful for any hint which brings progress to my developments
...

-- create table
CREATE TABLE testtable
(
  name varchar(256),
  number int4 DEFAULT 1,
  id varchar(64) NOT NULL,
  CONSTRAINT pk_id PRIMARY KEY
(id)
) 
WITHOUT OIDS;
ALTER TABLE testtable OWNER TO postgres;

-- insert dummy record
insert into testtable (id,number) values
('id_1', 1);

-- create test function
CREATE OR REPLACE FUNCTION savepoint_test
(
         
      in_no integer, 
         
      in_name varchar,
         
      in_id varchar
) RETURNS void
AS $$
BEGIN
        BEGIN
         
      SAVEPOINT my_savepoint;
         
      DELETE FROM testtable WHERE number = in_no;
         
      insert into testtable (id,number) values ('id_2',
2);
--        
       COMMIT;
         
      RELEASE SAVEPOINT my_savepoint;
        EXCEPTION
         
      WHEN unique_violation  THEN
         
          ROLLBACK TO my_savepoint;
        END;
END
$$ LANGUAGE plpgsql;

-- call test function
select * from savepoint_test(1, CAST('test-1'
AS VARCHAR), CAST('id_1' AS VARCHAR));


regards,

frank