v.21.3Backward Incompatible Changes

Fix TTL Creation for Functions Matching ORDER BY Key in ClickHouse

Fix creation of TTL in cases, when its expression is a function and it is the same as ORDER BY key. Now it's allowed to set custom aggregation to primary key columns in TTL with GROUP BY. Backward incompatible: For primary key columns, which are not in GROUP BY and aren't set explicitly now is applied function any instead of max, when TTL is expired. Also if you use TTL with WHERE or GROUP BY you can see exceptions at merges, while making rolling update. #15450 (Anton Popov).