uniq_keys
100000
250000
500000
1000000
5000000
create table t_{uniq_keys}(a UInt64) engine=MergeTree order by tuple()
insert into t_{uniq_keys} select number % {uniq_keys} from numbers_mt(5e7)
SELECT uniqExact(a) FROM remote('127.0.0.{{1,2}}', default, t_{uniq_keys}) SETTINGS max_threads=5
drop table t_{uniq_keys}