I am new to Postgresql and I try to do something so simple with Oracle.
I created a procedure with a simple code inside :
CREATE OR REPLACE PROCEDURE user.test_proc(IN param1 character varying)
LANGUAGE 'plpgsql'
AS $BODY$
DECLARE
i text;
BEGIN
if param1 = '1' then
insert into amian.test values ('1', '1');
rollback;
else
insert into amian.test values('2','2');
commit;
end if;
end;
$BODY$;
From unix environement I use psql :
psql –p port–d base–U user
\set AUTOCOMMIT off
call user.test_proc('2');
I have this error when the programm meets the COMMIT :
invalid transaction termination
What is wrong ? what should I do (I want to be with autocommit off) ?
Thank you
You can only use COMMIT and ROLLBACK in a procedure if the procedure is running in its own transaction (autocommit mode). See this quote from the documentation:
If CALL is executed in a transaction block, then the called procedure cannot execute transaction control statements. Transaction control statements are only allowed if CALL is executed in its own transaction.
Turning off autocommit in psql causes the client to send a BEGIN before the CALL statement, so you are in an explicitly started transaction. That causes the problem.
This restriction may be lifted at some point in the future, but currently that's the way it is.
Don't disable autocommit. You are risking long transactions, which can impair the health of your database.
Related
I am working with PostgreSQL with DBeaver. I would like for test purposes to make a procedure call in a transaction; then to Rollback it. I have written the following script:
DO $$
BEGIN
call MyProcedure();
ROLLBACK $$;
I have tried to run it in DBeaver console. I have got the following error:
SQL Error [42601]: ERROR: syntax error at end of input
It pointed out to the final $$.
What is wrong; and how could I reach my goal: to make a procedure call in a transaction; then to Rollback it?
For the DO block, you are missing the end
DO $$
BEGIN
RAISE NOTICE 'test';
ROLLBACK;
END $$;
But since you want to display a table content, you can't use an anonymous block but instead just start/end the transaction.
BEGIN;
select * from test;
call my_procedure();
select * from test;
ROLLBACK;
I'm new to Postgres, but with experience from Oracle. Trying to create a stored procedure which is going to:
Insert a row
Handle exceptions and in case of an exception insert a row into a log table by calling dedicated procedure
Emit an audit log record into a log table in case the whole procedure ran successfully
By pseudo code:
CREATE OR REPLACE PROCEDURE test.p_insert(IN p_test_param character varying)
LANGUAGE 'plpgsql'
SECURITY DEFINER
AS $BODY$
DECLARE
-- some declarations
BEGIN
BEGIN
INSERT INTO test.a(a) VALUES (p_test_param);
EXCEPTION
WHEN OTHERS THEN
-- GET STACKED DIAGNOSTICS
CALL test.p_insert_log(...); -- Inserts a row into a log table, another COMMIT may be required?
RAISE;
END;
COMMIT; -- CAN'T DO
BEGIN
IF (SELECT test.f_debug()) THEN
CALL test.p_insert_log(...); -- Audit the execution
END IF;
END;
COMMIT; -- CAN'T DO EITHER
END;
$$BODY$$;
However when I try to test the procedure out from an anonymous block in PgAdmin such as:
BEGIN;
DO
LANGUAGE plpgsql
$$
BEGIN
CALL test.p_insert(
p_test_param => 'test'
);
END;
$$
I'm getting an error ERROR: invalid transaction termination. How can I get rid of it? My objective is to let the procedure carry out the transaction control, I don't want the caller to COMMIT or ROLLBACK anything. If I remove both COMMIT commands from the code of the procedure, it executes well, however the invoker must explicitly COMMIT or REVOKE the transaction afterwards, which is not desired. In Oracle the pseudo code with COMMIT statements would work, in Postgres it doesn't seem to work as I would like to. Could you please help me out? Thanks
Your code will work as intended. Perhaps you made some mistake in calling the code:
you cannot call the procedure from a function
you cannot call the procedure in an explicitly started transaction:
BEGIN;
CALL p_insert('something); -- will fail
COMMIT;
According to the documentation (https://www.postgresql.org/docs/current/app-psql.html), even with AUTOCOMMIT set to off, PSQL issues an implicit BEGIN just before any command that is not already in a transaction block and is not itself a BEGIN or other transaction-control command, nor a command that cannot be executed inside a transaction block such as VACUUM. (Unfortunately CALL is not treated in the same way as VACCUM). And, according to Shaun Thomas (https://blog.2ndquadrant.com/pg-phriday-stored-procedures-postgres-11/), the invalid transaction termination error happens because it is not possible to close the current transaction (in this case the one initiated by PSQL) from within the procedure. I have tried with all the PSQL settings related to transaction control, but the invalid transaction termination error occurs with all of them; even if the commands file processed by PSQL contains only the CALL statement.
This is the procedure I'm calling:
create or replace procedure producto$cargar_imagenes(_super$ bigint, _archivo$ character varying) as $$
declare
_msg character varying;
_log rastro_proceso%ROWTYPE;
begin
perform rastro_proceso_temporal$insert(_super$);
perform producto$cargar_imagenes$biz(_super$, _archivo$);
if (_super$ is not null and _super$ > 0) then
perform producto$cargar_imagenes$log(_super$, _archivo$);
else
perform tarea_usuario$private$update(6519204281880642486, null);
end if;
commit;
end;
$$ language plpgsql set search_path = public;
It fails at the commit statement; it works if I comment it out.
Remove the SET clause. Per the documentation:
If a SET clause is attached to a procedure, then that procedure cannot execute transaction control statements (for example, COMMIT and ROLLBACK, depending on the language).
It appears that in pg11 (tested in version 11.6) you have the same problem if you include the "SECURITY DEFINER" clause in the procedure definition. So I guess SECURITY DEFINER qualifies as a "SET" clause.
When I remove SECURITY DEFINER I can include a COMMIT statement within the procedure definition without getting the ERROR:invalid transaction termination on the COMMIT statement.
It is also unfortunate that this is a run time error, and NOT a compilation error.
I have many stored procedure in my postgresql db,
and for some reason i need to run many procedure in transaction so if there is a error it will rollback.
is there any way to do this?
edit 1
i run this through java and for some reason i cant make transaction from java and i cant run query string, just store procedure only.
I actually thinking making procedure like this
CREATE OR REPLACE FUNCTION ldt_pricing_rule_v1_api.start()
RETURNS VOID
LANGUAGE PLPGSQL
SECURITY DEFINER
AS $$
BEGIN
EXECUTE 'begin transaction'
RETURN;
END
$$;
select ldt_pricing_rule_v1_api.start();
but it's will display this
ERROR: cannot begin/end transactions in PL/pgSQL
HINT: Use a BEGIN block with an EXCEPTION clause instead.
BEGIN ... COMMIT should to work.
BEGIN
SELECT func1();
SELECT func2();
COMMIT;
PostgreSQL 11 (it is not released yet) has procedures where you can control transactions explicitly. Procedures are started by CALL statement like any other databases. Now, PostgreSQL functions doesn't allow control transactions (explicitly).
Any PostgreSQL function is executed under transaction - explicitly started by user (like my example), or implicitly started by system (by autocommit mode).
So outer BEGIN starts explicit transaction:
BEGIN
SELECT func1();
SELECT func2();
COMMIT;
and if there is any unhandled fail, then only ROLLBACK command is available.
or implicit transaction:
CREATE OR REPLACE FUNCTION outerfx()
RETURNS void AS $$
BEGIN
PERFORM func1();
PERFORM func2();
END;
$$ LANGUAGE plpgsql;
SELECT outerfx(); -- starts outer transaction implicitly.
Now, functions func1, func2 are executed under transaction too.
I am seeking clarification of how to ensure an atomic transaction in a plpgsql function, and where the isolation level is set for this particular change to the database.
In the plpgsql function shown below, I want to make sure that BOTH the deletion AND the insertion succeed. I am getting an error when I try to wrap them in a single transaction:
ERROR: cannot begin/end transactions in PL/pgSQL
What happens during execution of the function below if another user has added a default behavior for circumstances ('RAIN', 'NIGHT', '45MPH') after this function has deleted the custom row but before it has had a chance to insert the custom row? Is there an implicit transaction wrapping the insert and delete so that both are rolled back if another user has changed either of the rows referenced by this function? Can I set the isolation level for this function?
create function foo(v_weather varchar(10), v_timeofday varchar(10), v_speed varchar(10),
v_behavior varchar(10))
returns setof CUSTOMBEHAVIOR
as $body$
begin
-- run-time error if either of these lines is un-commented
-- start transaction ISOLATION LEVEL READ COMMITTED;
-- or, alternatively, set transaction ISOLATION LEVEL READ COMMITTED;
delete from CUSTOMBEHAVIOR
where weather = 'RAIN' and timeofday = 'NIGHT' and speed= '45MPH' ;
-- if there is no default behavior insert a custom behavior
if not exists
(select id from DEFAULTBEHAVIOR where a = 'RAIN' and b = 'NIGHT' and c= '45MPH') then
insert into CUSTOMBEHAVIOR
(weather, timeofday, speed, behavior)
values
(v_weather, v_timeofday, v_speed, v_behavior);
end if;
return QUERY
select * from CUSTOMBEHAVIOR where ... ;
-- commit;
end
$body$ LANGUAGE plpgsql;
A plpgsql function automatically runs inside a transaction. It all succeeds or it all fails. The manual:
Functions and trigger procedures are always executed within a
transaction established by an outer query — they cannot start or
commit that transaction, since there would be no context for them to
execute in. However, a block containing an EXCEPTION clause
effectively forms a subtransaction that can be rolled back without
affecting the outer transaction. For more about that see Section 42.6.6.
So, if you need to, you can catch an exception that theoretically might occur (but is very unlikely).
Details on trapping errors in the manual.
Your function reviewed and simplified:
CREATE FUNCTION foo(v_weather text
, v_timeofday text
, v_speed text
, v_behavior text)
RETURNS SETOF custombehavior
LANGUAGE plpgsql AS
$func$
BEGIN
DELETE FROM custombehavior
WHERE weather = 'RAIN'
AND timeofday = 'NIGHT'
AND speed = '45MPH';
INSERT INTO custombehavior (weather, timeofday, speed, behavior)
SELECT v_weather, v_timeofday, v_speed, v_behavior
WHERE NOT EXISTS (
SELECT FROM defaultbehavior
WHERE a = 'RAIN'
AND b = 'NIGHT'
AND c = '45MPH'
);
RETURN QUERY
SELECT * FROM custombehavior WHERE ... ;
END
$func$;
If you actually need to begin/end transactions like indicated in the title look to SQL procedures in Postgres 11 or later (CREATE PROCEDURE). See:
In PostgreSQL, what is the difference between a “Stored Procedure” and other types of functions?
Update: after PostgreSQL version 11. you can control transaction inside Store Procedure.
=====
Before Version 10:
START TRANSACTION;
select foo() ;
COMMIT;
"Unfortunately Postgres has no stored procedures, so you always need to manage the transaction in the calling code" – a_horse_with_no_name
Transaction in an exception block - how?