SELECT '====array===='; DROP TABLE IF EXISTS t_arr; CREATE TABLE t_arr (a Array(UInt32)) ENGINE = MergeTree ORDER BY tuple() SETTINGS min_bytes_for_wide_part = 0; INSERT INTO t_arr VALUES ([1]) ([]) ([1, 2, 3]) ([1, 2]); SYSTEM DROP MARK CACHE; SELECT a.size0 FROM t_arr; SYSTEM FLUSH LOGS; SELECT ProfileEvents.Values[indexOf(ProfileEvents.Names, 'FileOpen')] FROM system.query_log WHERE (type = 'QueryFinish') AND (lower(query) LIKE lower('SELECT a.size0 FROM %t_arr%')) AND event_time > now() - INTERVAL 10 SECOND AND current_database = currentDatabase(); SELECT '====tuple===='; DROP TABLE IF EXISTS t_tup; CREATE TABLE t_tup (t Tuple(s String, u UInt32)) ENGINE = MergeTree ORDER BY tuple() SETTINGS min_bytes_for_wide_part = 0; INSERT INTO t_tup VALUES (('foo', 1)) (('bar', 2)) (('baz', 42)); SYSTEM DROP MARK CACHE; SELECT t.s FROM t_tup; SYSTEM DROP MARK CACHE; SELECT t.u FROM t_tup; SYSTEM FLUSH LOGS; SELECT ProfileEvents.Values[indexOf(ProfileEvents.Names, 'FileOpen')] FROM system.query_log WHERE (type = 'QueryFinish') AND (lower(query) LIKE lower('SELECT t._ FROM %t_tup%')) AND event_time > now() - INTERVAL 10 SECOND AND current_database = currentDatabase(); SELECT '====nullable===='; DROP TABLE IF EXISTS t_nul; CREATE TABLE t_nul (n Nullable(UInt32)) ENGINE = MergeTree ORDER BY tuple() SETTINGS min_bytes_for_wide_part = 0; INSERT INTO t_nul VALUES (1) (NULL) (2) (NULL); SYSTEM DROP MARK CACHE; SELECT n.null FROM t_nul; SYSTEM FLUSH LOGS; SELECT ProfileEvents.Values[indexOf(ProfileEvents.Names, 'FileOpen')] FROM system.query_log WHERE (type = 'QueryFinish') AND (lower(query) LIKE lower('SELECT n.null FROM %t_nul%')) AND event_time > now() - INTERVAL 10 SECOND AND current_database = currentDatabase(); SELECT '====map===='; SET allow_experimental_map_type = 1; DROP TABLE IF EXISTS t_map; CREATE TABLE t_map (m Map(String, UInt32)) ENGINE = MergeTree ORDER BY tuple() SETTINGS min_bytes_for_wide_part = 0; INSERT INTO t_map VALUES (map('a', 1, 'b', 2)) (map('a', 3, 'c', 4)), (map('b', 5, 'c', 6)); --- will read 4 files: keys.bin, keys.mrk2, size0.bin, size0.mrk2 SYSTEM DROP MARK CACHE; SELECT m.keys FROM t_map; SYSTEM DROP MARK CACHE; SELECT m.values FROM t_map; SYSTEM FLUSH LOGS; SELECT ProfileEvents.Values[indexOf(ProfileEvents.Names, 'FileOpen')] FROM system.query_log WHERE (type = 'QueryFinish') AND (lower(query) LIKE lower('SELECT m.% FROM %t_map%')) AND event_time > now() - INTERVAL 10 SECOND AND current_database = currentDatabase();