SET optimize_trivial_insert_select = 1; DROP TABLE IF EXISTS t_sparse_distinct; CREATE TABLE t_sparse_distinct (id UInt32, v UInt64) ENGINE = MergeTree ORDER BY id SETTINGS ratio_of_defaults_for_sparse_serialization = 0.9; SYSTEM STOP MERGES t_sparse_distinct; INSERT INTO t_sparse_distinct SELECT number, number % 6 FROM numbers(100000); INSERT INTO t_sparse_distinct SELECT number, number % 100 = 0 FROM numbers(100000); SELECT name, column, serialization_kind FROM system.parts_columns WHERE table = 't_sparse_distinct' AND database = currentDatabase() AND column = 'v' ORDER BY name; SELECT DISTINCT v FROM t_sparse_distinct ORDER BY v; DROP TABLE t_sparse_distinct;