Can I 'recompile' table returning functions after that table is ALTER-ed during database migration?

问题

I have a stored procedure that returns a record type. If I ALTER the table this stored procedure returns (let's say I add a column), I have to either disconnect my database session or re-run the CREATE OR REPLACE. When I don't I will get the error wrong record type supplied in RETURN NEXT.

Here's a script that fails when I run it in a single psql session:

CREATE TABLE p1(a INT, b TEXT);

CREATE OR REPLACE FUNCTION authenticate() RETURNS SETOF p1 as '
DECLARE
    player_row p1;
BEGIN

    -- query is more complicated but always returns zero or one rows
    SELECT p.* INTO player_row
    FROM p1 p;

    IF FOUND THEN
        RETURN NEXT player_row;

        -- more code in here..
    END IF;

    RETURN;
END;' LANGUAGE plpgsql ROWS 1;


ALTER TABLE p1 ADD COLUMN c VARCHAR(2);
INSERT INTO p1 VALUES(1,'a', 'c');
SELECT * FROM AUTHENTICATE();

Is there a Postgres command or setting with which I could automate the re-compilation of stored procedures? I tried @vao-tsun's suggestion of running DISCARD PLANS after the migrations, but unfortunately it did not help.

回答1:

you were looking for this DO statement:

CREATE TABLE p1(a INT, b TEXT);

CREATE OR REPLACE FUNCTION authenticate() RETURNS SETOF p1 as '
DECLARE
    player_row p1;
BEGIN

    -- query is more complicated but always returns zero or one rows
    SELECT p.* INTO player_row
    FROM p1 p;

    IF FOUND THEN
        RETURN NEXT player_row;

        -- more code in here..
    END IF;

    RETURN;
END;' LANGUAGE plpgsql ROWS 1;

ALTER TABLE p1 ADD COLUMN c VARCHAR(2);
INSERT INTO p1 VALUES(1,'a', 'c');

do $$ begin execute pg_get_functiondef('authenticate'::regproc); end; $$;

SELECT * FROM AUTHENTICATE();

but as a_horse_with_no_name suggests, you can just \c to reconnect with psql

来源：https://stackoverflow.com/questions/49653371/can-i-recompile-table-returning-functions-after-that-table-is-alter-ed-during

标签

postgresql

postgresql-10