DROP TABLE IF EXISTS test_lc_insert CREATE TABLE test_lc_insert (k1 LowCardinality(String), k2 LowCardinality(String)) ENGINE = MergeTree order by (k1, k2) INSERT INTO test_lc_insert(k1, k2) SELECT number%1000 AS k1, number%1001 AS k2 FROM numbers(2000000) DROP TABLE IF EXISTS test_lc_insert