-- Tags: no-parallel, no-random-merge-tree-settings drop table if exists pr_t; drop table if exists dist_t_different_dbs; drop table if exists shard_1.t_different_dbs; drop table if exists t_different_dbs; drop table if exists dist_t; drop table if exists t; create table t(a UInt64, b UInt64) engine=MergeTree order by a; system stop merges t; insert into t select number, number from numbers_mt(1e6); set enable_memory_bound_merging_of_aggregation_results = 1; set max_threads = 4; set optimize_aggregation_in_order = 1; set optimize_read_in_order = 1; set prefer_localhost_replica = 1; -- slightly different transforms will be generated by reading steps if we let settings randomisation to change this setting value -- set read_in_order_two_level_merge_threshold = 1000; create table dist_t as t engine = Distributed(test_cluster_two_shards, currentDatabase(), t, a % 2); -- { echoOn } -- explain pipeline select a from remote(test_cluster_two_shards, currentDatabase(), t) group by a; select a from remote(test_cluster_two_shards, currentDatabase(), t) group by a order by a limit 5 offset 100500; explain pipeline select a from remote(test_cluster_two_shards, currentDatabase(), dist_t) group by a; select a from remote(test_cluster_two_shards, currentDatabase(), dist_t) group by a order by a limit 5 offset 100500; -- { echoOff } -- set aggregation_in_order_max_block_bytes = '1Mi'; set max_block_size = 500; -- actual block size might be slightly bigger than the limit -- select max(bs) < 70000 from (select avg(a), max(blockSize()) as bs from remote(test_cluster_two_shards, currentDatabase(), t) group by a); -- beautiful case when we have different sorting key definitions in tables involved in distributed query => different plans => different sorting properties of local aggregation results -- create database if not exists shard_1; create table t_different_dbs(a UInt64, b UInt64) engine = MergeTree order by a; create table shard_1.t_different_dbs(a UInt64, b UInt64) engine = MergeTree order by tuple(); insert into t_different_dbs select number % 1000, number % 1000 from numbers_mt(1e6); insert into shard_1.t_different_dbs select number % 1000, number % 1000 from numbers_mt(1e6); create table dist_t_different_dbs as t engine = Distributed(test_cluster_two_shards_different_databases_with_local, '', t_different_dbs); -- { echoOn } -- explain pipeline select a, count() from dist_t_different_dbs group by a order by a limit 5 offset 500; select a, count() from dist_t_different_dbs group by a order by a limit 5 offset 500; select a, count() from dist_t_different_dbs group by a, b order by a limit 5 offset 500; -- { echoOff } -- create table pr_t(a UInt64, b UInt64) engine=MergeTree order by a; insert into pr_t select number % 1000, number % 1000 from numbers_mt(1e6); set allow_experimental_parallel_reading_from_replicas = 1; set parallel_replicas_for_non_replicated_merge_tree = 1; set max_parallel_replicas = 3; set use_hedged_requests = 0; set cluster_for_parallel_replicas = 'test_cluster_one_shard_three_replicas_localhost'; set distributed_aggregation_memory_efficient=1; select count() from pr_t; -- { echoOn } -- explain pipeline select a from pr_t group by a order by a limit 5 offset 500; select a, count() from pr_t group by a order by a limit 5 offset 500; select a, count() from pr_t group by a, b order by a limit 5 offset 500; -- { echoOff } -- drop table if exists pr_t; drop table if exists dist_t_different_dbs; drop table if exists shard_1.t_different_dbs; drop table if exists t_different_dbs; drop table if exists dist_t; drop table if exists t;