DROP TABLE IF EXISTS test_table; CREATE TABLE test_table ( `timestamp` DateTime, `value` UInt64, `day` Date ALIAS toDate(timestamp), `day1` Date ALIAS day + 1, `day2` Date ALIAS day1 + 1, `time` DateTime ALIAS timestamp ) ENGINE = MergeTree PARTITION BY toYYYYMMDD(timestamp) ORDER BY timestamp SETTINGS index_granularity = 1; INSERT INTO test_table(timestamp, value) SELECT toDateTime('2020-01-01 12:00:00'), 1 FROM numbers(10); INSERT INTO test_table(timestamp, value) SELECT toDateTime('2020-01-02 12:00:00'), 1 FROM numbers(10); INSERT INTO test_table(timestamp, value) SELECT toDateTime('2020-01-03 12:00:00'), 1 FROM numbers(10); set optimize_respect_aliases = 1; SELECT 'test-partition-prune'; SELECT COUNT() = 10 FROM test_table WHERE day = '2020-01-01' SETTINGS max_rows_to_read = 10; SELECT t = '2020-01-03' FROM (SELECT day AS t FROM test_table WHERE t = '2020-01-03' GROUP BY t SETTINGS max_rows_to_read = 10); SELECT COUNT() = 10 FROM test_table WHERE day = '2020-01-01' UNION ALL SELECT 1 FROM numbers(1) SETTINGS max_rows_to_read = 11; SELECT COUNT() = 0 FROM (SELECT toDate('2019-01-01') AS day, day AS t FROM test_table PREWHERE t = '2020-01-03' WHERE t = '2020-01-03' GROUP BY t ); SELECT 'test-join'; SELECT day = '2020-01-03' FROM ( SELECT toDate('2020-01-03') AS day FROM numbers(1) ) AS a INNER JOIN ( SELECT day FROM test_table WHERE day = '2020-01-03' GROUP BY day ) AS b ON a.day = b.day SETTINGS max_rows_to_read = 11; SELECT day = '2020-01-01' FROM ( SELECT day FROM test_table WHERE day = '2020-01-01' GROUP BY day ) AS a INNER JOIN ( SELECT toDate('2020-01-01') AS day FROM numbers(1) ) AS b ON a.day = b.day SETTINGS max_rows_to_read = 11; SELECT 'alias2alias'; SELECT COUNT() = 10 FROM test_table WHERE day1 = '2020-01-02' SETTINGS max_rows_to_read = 10; SELECT t = '2020-01-03' FROM (SELECT day1 AS t FROM test_table WHERE t = '2020-01-03' GROUP BY t SETTINGS max_rows_to_read = 10); SELECT t = '2020-01-03' FROM (SELECT day2 AS t FROM test_table WHERE t = '2020-01-03' GROUP BY t SETTINGS max_rows_to_read = 10); SELECT COUNT() = 10 FROM test_table WHERE day1 = '2020-01-03' UNION ALL SELECT 1 FROM numbers(1) SETTINGS max_rows_to_read = 11; SELECT COUNT() = 0 FROM (SELECT toDate('2019-01-01') AS day1, day1 AS t FROM test_table PREWHERE t = '2020-01-03' WHERE t = '2020-01-03' GROUP BY t ); SELECT day1 = '2020-01-04' FROM test_table PREWHERE day1 = '2020-01-04' WHERE day1 = '2020-01-04' GROUP BY day1 SETTINGS max_rows_to_read = 10; ALTER TABLE test_table add column array Array(UInt8) default [1, 2, 3]; ALTER TABLE test_table add column struct.key Array(UInt8) default [2, 4, 6], add column struct.value Array(UInt8) alias array; SELECT 'array-join'; set max_rows_to_read = 10; SELECT count() == 10 FROM test_table WHERE day = '2020-01-01'; SELECT sum(struct.key) == 30, sum(struct.value) == 30 FROM (SELECT struct.key, struct.value FROM test_table array join struct WHERE day = '2020-01-01'); SELECT 'lambda'; -- lambda parameters in filter should not be rewrite SELECT count() == 10 FROM test_table WHERE arrayMap((day) -> day + 1, [1,2,3]) [1] = 2 AND day = '2020-01-03'; set max_rows_to_read = 0; SELECT 'optimize_read_in_order'; EXPLAIN SELECT day AS s FROM test_table ORDER BY s LIMIT 1 SETTINGS optimize_read_in_order = 0; EXPLAIN SELECT day AS s FROM test_table ORDER BY s LIMIT 1 SETTINGS optimize_read_in_order = 1; EXPLAIN SELECT toDate(timestamp) AS s FROM test_table ORDER BY toDate(timestamp) LIMIT 1 SETTINGS optimize_read_in_order = 1; SELECT 'optimize_aggregation_in_order'; EXPLAIN SELECT day, count() AS s FROM test_table GROUP BY day SETTINGS optimize_aggregation_in_order = 0; EXPLAIN SELECT day, count() AS s FROM test_table GROUP BY day SETTINGS optimize_aggregation_in_order = 1; EXPLAIN SELECT toDate(timestamp), count() AS s FROM test_table GROUP BY toDate(timestamp) SETTINGS optimize_aggregation_in_order = 1; DROP TABLE test_table; SELECT 'second-index'; DROP TABLE IF EXISTS test_index; CREATE TABLE test_index ( `key_string` String, `key_uint32` ALIAS toUInt32(key_string), INDEX idx toUInt32(key_string) TYPE set(0) GRANULARITY 1 ) ENGINE = MergeTree PARTITION BY tuple() PRIMARY KEY tuple() ORDER BY key_string SETTINGS index_granularity = 1; INSERT INTO test_index SELECT * FROM numbers(10); set max_rows_to_read = 1; SELECT COUNT() == 1 FROM test_index WHERE key_uint32 = 1; SELECT COUNT() == 1 FROM test_index WHERE toUInt32(key_string) = 1; DROP TABLE IF EXISTS test_index; -- check alias column can be used to match projections drop table if exists p; create table pd (dt DateTime, i int, dt_m DateTime alias toStartOfMinute(dt)) engine Distributed(test_shard_localhost, currentDatabase(), 'pl'); create table pl (dt DateTime, i int, projection p (select sum(i) group by toStartOfMinute(dt))) engine MergeTree order by dt; insert into pl values ('2020-10-24', 1); set max_rows_to_read = 2; select sum(i) from pd group by dt_m settings allow_experimental_projection_optimization = 1, force_optimize_projection = 1; drop table pd; drop table pl; drop table if exists t; create temporary table t (x UInt64, y alias x); insert into t values (1); select sum(x), sum(y) from t; drop table t;