drop table if exists tp_1; drop table if exists tp_2; create table tp_1 (x Int32, y Int32, projection p (select x, y order by x)) engine = ReplicatedMergeTree('/clickhouse/tables/{shard}/01710_projection_fetch_' || currentDatabase(), '1_{replica}') order by y settings min_rows_for_compact_part = 2, min_rows_for_wide_part = 4, min_bytes_for_compact_part = 16, min_bytes_for_wide_part = 32; create table tp_2 (x Int32, y Int32, projection p (select x, y order by x)) engine = ReplicatedMergeTree('/clickhouse/tables/{shard}/01710_projection_fetch_' || currentDatabase(), '2_{replica}') order by y settings min_rows_for_compact_part = 2, min_rows_for_wide_part = 4, min_bytes_for_compact_part = 16, min_bytes_for_wide_part = 32; insert into tp_1 select number, number from numbers(3); system sync replica tp_2; select * from tp_2 order by x; insert into tp_1 select number, number from numbers(5); system sync replica tp_2; select * from tp_2 order by x; -- test projection creation, materialization, clear and drop alter table tp_1 add projection pp (select x, count() group by x); system sync replica tp_2; select count() from system.projection_parts where database = currentDatabase() and table = 'tp_2' and name = 'pp' and active; show create table tp_2; -- all other three operations are mutations set mutations_sync = 2; alter table tp_1 materialize projection pp; select count() from system.projection_parts where database = currentDatabase() and table = 'tp_2' and name = 'pp' and active; show create table tp_2; alter table tp_1 clear projection pp; system sync replica tp_2; select * from system.projection_parts where database = currentDatabase() and table = 'tp_2' and name = 'pp' and active; show create table tp_2; alter table tp_1 drop projection pp; system sync replica tp_2; select * from system.projection_parts where database = currentDatabase() and table = 'tp_2' and name = 'pp' and active; show create table tp_2; drop table if exists tp_1; drop table if exists tp_2;