text: DROP TABLE IF EXISTS test.dst;
  DROP TABLE IF EXISTS test.buffer;
  SET send_logs_level = 'error';
  
  CREATE TABLE test.dst (x UInt64, y UInt64) ENGINE = MergeTree ORDER BY tuple();
  CREATE TABLE test.buffer (x UInt64, y UInt64) ENGINE = Buffer(test, dst, 1, 99999, 99999, 1, 1, 99999, 99999);
  
  INSERT INTO test.buffer VALUES (1, 100);
  INSERT INTO test.buffer VALUES (2, 200);
  INSERT INTO test.buffer VALUES (3, 300);
  SELECT 'init';
  SELECT * FROM test.dst ORDER BY x;
  SELECT '-';
  SELECT * FROM test.buffer ORDER BY x;
  
  ALTER TABLE test.dst DROP COLUMN x, MODIFY COLUMN y String, ADD COLUMN z String DEFAULT 'DEFZ';
  
  INSERT INTO test.buffer VALUES (4, 400);
  SELECT 'alt';
  SELECT * FROM test.dst ORDER BY y;
  SELECT '-';
  SELECT * FROM test.buffer ORDER BY y;
  
  OPTIMIZE TABLE test.buffer;
  SELECT 'opt';
  SELECT * FROM test.dst ORDER BY y;
  SELECT '-';
  SELECT * FROM test.buffer ORDER BY y;
  
  SET send_logs_level = 'warning';
  DROP TABLE IF EXISTS test.dst;
  DROP TABLE IF EXISTS test.buffer;
  