Hi,
the docu about the Read Committed Transaction Isolation Level pointed out: "... The point at issue here is whether or not within a single command we see an absolutely consistent view of the database.".
Because i dont want to use the Serializable Transaction Isolation Level or table locks if it not necessary i have one question:
Would the insert command with that subselect treated as one single command and can i so prevent a race condition between multiple function calls?
CREATE OR REPLACE FUNCTION "public"."count_parameter" (name, integer) RETURNS "pg_catalog"."void" AS' BEGIN
INSERT INTO parameter (parameter_name, parameter_value)
SELECT $1, $2 WHERE (
SELECT COUNT(*) = 0 FROM parameter WHERE parameter_name = $1
);
IF NOT FOUND THEN
UPDATE parameter SET parameter_value = parameter_value + $2
WHERE parameter_name = $1;
END IF;RETURN;
END; 'LANGUAGE 'plpgsql' VOLATILE CALLED ON NULL INPUT SECURITY INVOKER;
best regards,
thomas
---------------------------(end of broadcast)--------------------------- TIP 9: the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
