Hi, everyone!
I have a table:
create table testpr(id serial,priority integer,unique(priority) DEFERRABLE, primary key(id));
and a trigger which, when added to this table, automatically sets priority as the maximum value +1
CREATE OR REPLACE FUNCTION PriorityCheck() RETURNS trigger AS $$
BEGIN
NEW.priority := (SELECT coalesce(max(priority),0)+1 from testpr);
RETURN NEW;
END;
$$ LANGUAGE plpgsql;
CREATE TRIGGER InsertTrigger BEFORE INSERT on testpr for EACH ROW
EXECUTE PROCEDURE PriorityCheck();
Will the priority be serial, when there is multithreaded addition of values to the table?
Which is:
Thread 1 insert into testpr(priority) values (1), (1), (1), (1), (1), (1), (1);
Thread 2 insert into testpr(priority) values (2), (2), (2), (2), (2), (2), (2);
The result (priority):
Thread 1: (1) (2) (3) (4) (5) (6) (7)
Thread 2: (8) (9) (10) (11) (12) (13) (14)
--
Arsen Arutyunyan