-- Tags: no-backward-compatibility-check SET mutations_sync = 2; DROP TABLE IF EXISTS t_sparse_alter; CREATE TABLE t_sparse_alter (id UInt64, u UInt64, s String) ENGINE = MergeTree ORDER BY id SETTINGS ratio_of_defaults_for_sparse_serialization = 0.5; INSERT INTO t_sparse_alter SELECT number, if (number % 11 = 0, number, 0), if (number % 13 = 0, toString(number), '') FROM numbers(2000); SELECT column, serialization_kind FROM system.parts_columns WHERE database = currentDatabase() AND table = 't_sparse_alter' AND active ORDER BY column; SELECT uniqExact(u), uniqExact(s) FROM t_sparse_alter; ALTER TABLE t_sparse_alter DROP COLUMN s, RENAME COLUMN u TO t; ALTER TABLE t_sparse_alter MODIFY COLUMN t UInt16; SELECT column, serialization_kind FROM system.parts_columns WHERE database = currentDatabase() AND table = 't_sparse_alter' AND active ORDER BY column; SELECT uniqExact(t) FROM t_sparse_alter; DETACH TABLE t_sparse_alter; ATTACH TABLE t_sparse_alter; SELECT column, serialization_kind FROM system.parts_columns WHERE database = currentDatabase() AND table = 't_sparse_alter' AND active ORDER BY column; SELECT uniqExact(t) FROM t_sparse_alter; DROP TABLE t_sparse_alter;