30000000000 millions 50 100 window 10 1000 10000 create table sorted_{millions}m engine MergeTree order by k as select number % 100 k, rand() v from numbers_mt(1000000 * {millions}) optimize table sorted_{millions}m final select k, groupArraySorted({window})(v) from sorted_{millions}m group by k format Null select k % 10 kk, groupArraySorted({window})(v) from sorted_{millions}m group by kk format Null drop table if exists sorted_{millions}m