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CREATE TABLE toasttest(descr text, cnt int DEFAULT 0, f1 text, f2 text);
INSERT INTO toasttest(descr, f1, f2) VALUES('two-compressed', repeat('1234567890',1000), repeat('1234567890',1000));
INSERT INTO toasttest(descr, f1, f2) VALUES('two-toasted', repeat('1234567890',30000), repeat('1234567890',50000));
INSERT INTO toasttest(descr, f1, f2) VALUES('one-compressed,one-null', NULL, repeat('1234567890',1000));
INSERT INTO toasttest(descr, f1, f2) VALUES('one-toasted,one-null', NULL, repeat('1234567890',50000));
-- check whether indirect tuples works on the most basic level
SELECT descr, substring(make_tuple_indirect(toasttest)::text, 1, 200) FROM toasttest;
-- modification without changing varlenas
UPDATE toasttest SET cnt = cnt +1 RETURNING substring(toasttest::text, 1, 200);
-- modification without modifying assigned value
UPDATE toasttest SET cnt = cnt +1, f1 = f1 RETURNING substring(toasttest::text, 1, 200);
-- modification modifying, but effectively not changing
UPDATE toasttest SET cnt = cnt +1, f1 = f1||'' RETURNING substring(toasttest::text, 1, 200);
UPDATE toasttest SET cnt = cnt +1, f1 = '-'||f1||'-' RETURNING substring(toasttest::text, 1, 200);
SELECT substring(toasttest::text, 1, 200) FROM toasttest;
-- check we didn't screw with main/toast tuple visibility
VACUUM FREEZE toasttest;
SELECT substring(toasttest::text, 1, 200) FROM toasttest;
-- now create a trigger that forces all Datums to be indirect ones
CREATE FUNCTION update_using_indirect()
RETURNS trigger
LANGUAGE plpgsql AS $$
BEGIN
NEW := make_tuple_indirect(NEW);
RETURN NEW;
END$$;
CREATE TRIGGER toasttest_update_indirect
BEFORE INSERT OR UPDATE
ON toasttest
FOR EACH ROW
EXECUTE PROCEDURE update_using_indirect();
-- modification without changing varlenas
UPDATE toasttest SET cnt = cnt +1 RETURNING substring(toasttest::text, 1, 200);
-- modification without modifying assigned value
UPDATE toasttest SET cnt = cnt +1, f1 = f1 RETURNING substring(toasttest::text, 1, 200);
-- modification modifying, but effectively not changing
UPDATE toasttest SET cnt = cnt +1, f1 = f1||'' RETURNING substring(toasttest::text, 1, 200);
UPDATE toasttest SET cnt = cnt +1, f1 = '-'||f1||'-' RETURNING substring(toasttest::text, 1, 200);
INSERT INTO toasttest(descr, f1, f2) VALUES('one-toasted,one-null, via indirect', repeat('1234567890',30000), NULL);
SELECT substring(toasttest::text, 1, 200) FROM toasttest;
-- check we didn't screw with main/toast tuple visibility
VACUUM FREEZE toasttest;
SELECT substring(toasttest::text, 1, 200) FROM toasttest;
DROP TABLE toasttest;
DROP FUNCTION update_using_indirect();
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