-- Tags: no-parallel drop table if exists ttl; create table ttl (d Date, a Int) engine = MergeTree order by a partition by toDayOfMonth(d) settings remove_empty_parts = 0; insert into ttl values (toDateTime('2000-10-10 00:00:00'), 1); insert into ttl values (toDateTime('2000-10-10 00:00:00'), 2); insert into ttl values (toDateTime('2100-10-10 00:00:00'), 3); insert into ttl values (toDateTime('2100-10-10 00:00:00'), 4); alter table ttl modify ttl d + interval 1 day; select sleep(1) format Null; -- wait if very fast merge happen optimize table ttl partition 10 final; select * from ttl order by d; drop table if exists ttl;