CREATE TABLE test_set (k UInt32, x UInt32, INDEX idx (x) TYPE set(10) GRANULARITY 1) ENGINE = MergeTree ORDER BY k SETTINGS index_granularity = 111; SYSTEM STOP MERGES INSERT INTO test_set SELECT number, number DIV 100 + rand() % 7 FROM numbers(3000000) SETTINGS max_insert_threads = 4; SELECT count() FROM test_set WHERE x = 1234 SETTINGS max_threads = 8; SYSTEM START MERGES DROP TABLE IF EXISTS test_set