diff --git a/dbms/src/DataStreams/MergingAggregatedMemoryEfficientBlockInputStream.cpp b/dbms/src/DataStreams/MergingAggregatedMemoryEfficientBlockInputStream.cpp
index 5c64c0c858f..44a5889338b 100644
--- a/dbms/src/DataStreams/MergingAggregatedMemoryEfficientBlockInputStream.cpp
+++ b/dbms/src/DataStreams/MergingAggregatedMemoryEfficientBlockInputStream.cpp
@@ -28,6 +28,9 @@ String MergingAggregatedMemoryEfficientBlockInputStream::getID() const
 Block MergingAggregatedMemoryEfficientBlockInputStream::readImpl()
 {
 	/// Если child - RemoteBlockInputStream, то отправляет запрос на все удалённые серверы, инициируя вычисления.
+	/** NOTE: Если соединения ещё не установлены, то устанавливает их последовательно.
+	  * И отправляет запрос последовательно. Это медленно.
+	  */
 	if (!started)
 	{
 		started = true;
@@ -154,11 +157,7 @@ Block MergingAggregatedMemoryEfficientBlockInputStream::readImpl()
 					LOG_TRACE(&Logger::get("MergingAggregatedMemoryEfficient"), "Having block without bucket: will split.");
 
 					input.splitted_blocks = aggregator.convertBlockToTwoLevel(input.block);
-
-					/** Нельзя уничтожать исходный блок.
-						* Потому что он владеет Arena с состояниями агрегатных функций,
-						*  а splitted_blocks ей не владеют, но ссылаются на эти состояния.
-						*/
+					input.block = Block();
 				}
 
 				/// Блоки, которые мы получили разрезанием одноуровневых блоков.
diff --git a/dbms/src/Interpreters/Aggregator.cpp b/dbms/src/Interpreters/Aggregator.cpp
index 47088d1a8cf..ce615fb53d4 100644
--- a/dbms/src/Interpreters/Aggregator.cpp
+++ b/dbms/src/Interpreters/Aggregator.cpp
@@ -1814,6 +1814,9 @@ void NO_INLINE Aggregator::convertBlockToTwoLevelImpl(
 	size_t rows = source.rowsInFirstColumn();
 	size_t columns = source.columns();
 
+	/// Для каждого номера корзины создадим фильтр, где будут отмечены строки, относящиеся к этой корзине.
+	std::vector<IColumn::Filter> filters(destinations.size());
+
 	/// Для всех строчек.
 	for (size_t i = 0; i < rows; ++i)
 	{
@@ -1826,15 +1829,33 @@ void NO_INLINE Aggregator::convertBlockToTwoLevelImpl(
 		/// Этот ключ нам больше не нужен.
 		method.onExistingKey(key, keys, *pool);
 
+		auto & filter = filters[bucket];
+
+		if (unlikely(filter.empty()))
+			filter.resize_fill(rows);
+
+		filter[i] = 1;
+	}
+
+	for (size_t bucket = 0, size = destinations.size(); bucket < size; ++bucket)
+	{
+		const auto & filter = filters[bucket];
+
+		if (filter.empty())
+			continue;
+
 		Block & dst = destinations[bucket];
-		if (unlikely(!dst))
-		{
-			dst = source.cloneEmpty();
-			dst.info.bucket_num = bucket;
-		}
+		dst.info.bucket_num = bucket;
 
 		for (size_t j = 0; j < columns; ++j)
-			dst.unsafeGetByPosition(j).column.get()->insertFrom(*source.unsafeGetByPosition(j).column.get(), i);
+		{
+			const ColumnWithTypeAndName & src_col = source.unsafeGetByPosition(j);
+			dst.insert({src_col.column->filter(filter), src_col.type, src_col.name});
+
+			/** Вставленные в блок столбцы типа ColumnAggregateFunction будут владеть состояниями агрегатных функций
+			  *  путём удержания SharedPtr-а на исходный столбец. См. ColumnAggregateFunction.h
+			  */
+		}
 	}
 }
 
diff --git a/dbms/tests/queries/0_stateless/00223_distributed_aggregation_memory_efficient.reference b/dbms/tests/queries/0_stateless/00223_distributed_aggregation_memory_efficient.reference
index fb3ea660581..8e01654f052 100644
--- a/dbms/tests/queries/0_stateless/00223_distributed_aggregation_memory_efficient.reference
+++ b/dbms/tests/queries/0_stateless/00223_distributed_aggregation_memory_efficient.reference
@@ -78,4 +78,14 @@
 1	1	1
 1	1	1
 1	1	1
+1	1	1
+1	1	1
+1	1	1
+1	1	1
+1	1	1
+1	1	1
+1	1	1
+1	1	1
+1	1	1
+1	1	1
 2
diff --git a/dbms/tests/queries/0_stateless/00223_distributed_aggregation_memory_efficient.sql b/dbms/tests/queries/0_stateless/00223_distributed_aggregation_memory_efficient.sql
index cfb35cf1cc8..3462e48a58b 100644
--- a/dbms/tests/queries/0_stateless/00223_distributed_aggregation_memory_efficient.sql
+++ b/dbms/tests/queries/0_stateless/00223_distributed_aggregation_memory_efficient.sql
@@ -115,6 +115,17 @@ SELECT sum(c = 1) IN (0, 5), sum(c = 2) IN (5, 10), sum(c) IN (10, 15, 20) FROM
 SELECT sum(c = 1) IN (0, 5), sum(c = 2) IN (5, 10), sum(c) IN (10, 15, 20) FROM (SELECT number AS k1, number + 1 AS k2, count() AS c FROM remote('127.0.0.{1,2}', test.numbers_10) WHERE number < (randConstant() % 2 ? 5 : 10) GROUP BY k1, k2 HAVING count() > 0 ORDER BY k1, k2);
 SELECT sum(c = 1) IN (0, 5), sum(c = 2) IN (5, 10), sum(c) IN (10, 15, 20) FROM (SELECT number AS k1, number + 1 AS k2, count() AS c FROM remote('127.0.0.{1,2}', test.numbers_10) WHERE number < (randConstant() % 2 ? 5 : 10) GROUP BY k1, k2 HAVING count() > 0 ORDER BY k1, k2);
 
+SELECT sum(c = 20) IN (5, 10), sum(c = 10) IN (0, 5), sum(u != 10) = 0 FROM (SELECT intDiv(number, 10) AS k1, k1 + 1 AS k2, count() AS c, uniq(number) AS u FROM remote('127.0.0.{1,2}', test.numbers_10) WHERE number < (randConstant() % 2 ? 50 : 100) GROUP BY k1, k2 HAVING count() > 0 ORDER BY k1, k2);
+SELECT sum(c = 20) IN (5, 10), sum(c = 10) IN (0, 5), sum(u != 10) = 0 FROM (SELECT intDiv(number, 10) AS k1, k1 + 1 AS k2, count() AS c, uniq(number) AS u FROM remote('127.0.0.{1,2}', test.numbers_10) WHERE number < (randConstant() % 2 ? 50 : 100) GROUP BY k1, k2 HAVING count() > 0 ORDER BY k1, k2);
+SELECT sum(c = 20) IN (5, 10), sum(c = 10) IN (0, 5), sum(u != 10) = 0 FROM (SELECT intDiv(number, 10) AS k1, k1 + 1 AS k2, count() AS c, uniq(number) AS u FROM remote('127.0.0.{1,2}', test.numbers_10) WHERE number < (randConstant() % 2 ? 50 : 100) GROUP BY k1, k2 HAVING count() > 0 ORDER BY k1, k2);
+SELECT sum(c = 20) IN (5, 10), sum(c = 10) IN (0, 5), sum(u != 10) = 0 FROM (SELECT intDiv(number, 10) AS k1, k1 + 1 AS k2, count() AS c, uniq(number) AS u FROM remote('127.0.0.{1,2}', test.numbers_10) WHERE number < (randConstant() % 2 ? 50 : 100) GROUP BY k1, k2 HAVING count() > 0 ORDER BY k1, k2);
+SELECT sum(c = 20) IN (5, 10), sum(c = 10) IN (0, 5), sum(u != 10) = 0 FROM (SELECT intDiv(number, 10) AS k1, k1 + 1 AS k2, count() AS c, uniq(number) AS u FROM remote('127.0.0.{1,2}', test.numbers_10) WHERE number < (randConstant() % 2 ? 50 : 100) GROUP BY k1, k2 HAVING count() > 0 ORDER BY k1, k2);
+SELECT sum(c = 20) IN (5, 10), sum(c = 10) IN (0, 5), sum(u != 10) = 0 FROM (SELECT intDiv(number, 10) AS k1, k1 + 1 AS k2, count() AS c, uniq(number) AS u FROM remote('127.0.0.{1,2}', test.numbers_10) WHERE number < (randConstant() % 2 ? 50 : 100) GROUP BY k1, k2 HAVING count() > 0 ORDER BY k1, k2);
+SELECT sum(c = 20) IN (5, 10), sum(c = 10) IN (0, 5), sum(u != 10) = 0 FROM (SELECT intDiv(number, 10) AS k1, k1 + 1 AS k2, count() AS c, uniq(number) AS u FROM remote('127.0.0.{1,2}', test.numbers_10) WHERE number < (randConstant() % 2 ? 50 : 100) GROUP BY k1, k2 HAVING count() > 0 ORDER BY k1, k2);
+SELECT sum(c = 20) IN (5, 10), sum(c = 10) IN (0, 5), sum(u != 10) = 0 FROM (SELECT intDiv(number, 10) AS k1, k1 + 1 AS k2, count() AS c, uniq(number) AS u FROM remote('127.0.0.{1,2}', test.numbers_10) WHERE number < (randConstant() % 2 ? 50 : 100) GROUP BY k1, k2 HAVING count() > 0 ORDER BY k1, k2);
+SELECT sum(c = 20) IN (5, 10), sum(c = 10) IN (0, 5), sum(u != 10) = 0 FROM (SELECT intDiv(number, 10) AS k1, k1 + 1 AS k2, count() AS c, uniq(number) AS u FROM remote('127.0.0.{1,2}', test.numbers_10) WHERE number < (randConstant() % 2 ? 50 : 100) GROUP BY k1, k2 HAVING count() > 0 ORDER BY k1, k2);
+SELECT sum(c = 20) IN (5, 10), sum(c = 10) IN (0, 5), sum(u != 10) = 0 FROM (SELECT intDiv(number, 10) AS k1, k1 + 1 AS k2, count() AS c, uniq(number) AS u FROM remote('127.0.0.{1,2}', test.numbers_10) WHERE number < (randConstant() % 2 ? 50 : 100) GROUP BY k1, k2 HAVING count() > 0 ORDER BY k1, k2);
+
 DROP TABLE test.numbers_10;
 
 SELECT count() FROM remote('127.0.0.{1,2}', system.one);