SaltTan

drop table if exists t1;
drop table if exists t2;
CREATE TABLE t1 (n Int8, s1 String) ENGINE = Log;
CREATE TABLE t2 (n Int8, s2 String) ENGINE = Log;

insert into t1 values (1, 'One'), (2, 'Two'), (3, 'Three'), (1, 'One`'), (4, 'Four');
insert into t2 values (1, 'Un'), (2, 'Deux'), (3, 'Trois'), (1, 'Un`'), (5, 'Cinq');

20.1.2.4

SaltTan

CREATE TABLE amt
(
    `ip` Int32,
    `first` SimpleAggregateFunction(min, DateTime),
    `last` SimpleAggregateFunction(max, DateTime)
)
ENGINE = AggregatingMergeTree()
ORDER BY ip;

ALTER TABLE amt MODIFY TTL last + toIntervalMinute(10);

SaltTan

SELECT f_string 
FROM distributed_table 
WHERE partition_key = '2019-08-23' AND pk_f1 = 118129 AND pk_f2= -2
GROUP BY f_string

2019.08.26 19:35:32.294127 [ 150 ] {905a17ff-ac63-4ea8-aca9-1f8410c67bcb} <Debug> executeQuery: Query pipeline:
Expression
 MergeSorting
  PartialSorting
   Expression

SaltTan

SELECT f_string 
FROM distributed_table 
WHERE partition_key = '2019-08-23' AND pk_f1 = 118129 AND pk_f2= -2
GROUP BY f_string LIMIT 10

2019.08.27 17:56:26.823105 [ 56 ] {e283771b-f472-4b75-a999-95cc7b7bc216} <Debug> executeQuery: Query pipeline:
Limit
 Expression
  Expression
   MergingAggregatedMemoryEfficient