Now ALTER MODIFY TTL triggers MATERIALIZE TTL that runs a merge for every part in the table. Not only it requires a lot of resources, it might also be completely useless (I might want to increase the TTL period, for example). MATERIALIZE...
TTL of columns and tables TTL can set the life cycle of the value, it can be set for the entire table, or it can be set separately for each column field.
01.04.2020 · Clickhouse - TTL vs ALTER DELETE 3 I'd like to understand if the data removal mechanism used by the Clickhouse TTL feature is the same as for the ALTER DELETE mutation. In particular, is the following statement ( documentation) referring the ALTER DELETE mutation also valid for the TTL feature: