DROP TABLE IF EXISTS tab_00625; set allow_deprecated_syntax_for_merge_tree=1; CREATE TABLE tab_00625 ( date Date, key UInt32, testMap Nested( k UInt16, v UInt64) ) ENGINE = SummingMergeTree(date, (date, key), 1); INSERT INTO tab_00625 SELECT today(), number, [toUInt16(number)], [number] FROM system.numbers LIMIT 8190; INSERT INTO tab_00625 SELECT today(), number + 8190, [toUInt16(number)], [number + 8190] FROM system.numbers LIMIT 10; OPTIMIZE TABLE tab_00625; DROP TABLE tab_00625;