fklock-wide.sql

-- Setup: done once per candidate; cluster re-cloned for each iteration.
/*
BEGIN;
DROP TABLE IF EXISTS test_wide;
-- Focus is on column comparison costs in heap_update, so use UNLOGGED.
CREATE UNLOGGED TABLE test_wide (
	k text,
	v int
)
-- Fill two tuples per page, leaving space for a HOT update of each.
WITH (fillfactor = 50);
-- Suppress TOAST activity.
ALTER TABLE test_wide ALTER k SET STORAGE PLAIN;
-- Make a bunch of tuples of ~2000 bytes.
INSERT INTO test_wide
SELECT repeat(md5(n::text), 60), n FROM generate_series(1,100000) t(n);

ALTER TABLE test_wide ADD UNIQUE (k);
COMMIT;
*/

BEGIN;
-- master times: 18863.307, 18501.506, 18752.469
-- patched times: 17591.783, 18297.841, 17204.112
UPDATE test_wide SET v = v + 1;
SELECT pg_sleep(1); -- time for stats to transfer
COMMIT;

-- Confirm we that we got HOT updates.
\x on
SELECT * FROM pg_stat_all_tables WHERE relid = 'test_wide'::regclass;
\x off
SELECT pg_size_pretty(pg_relation_size('test_wide'));