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
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