CREATE TABLE lwd_test ( id UInt64, value String, ) ENGINE=MergeTree() ORDER BY id; INSERT INTO lwd_test SELECT number, randomString(100) FROM system.numbers LIMIT 10000000; OPTIMIZE TABLE lwd_test FINAL; 1 1 DELETE FROM lwd_test WHERE id < 9999999; SELECT id, length(value) FROM lwd_test ORDER BY id LIMIT 1 DROP TABLE lwd_test