diff --git a/dbms/include/DB/Storages/StorageReplicatedMergeTree.h b/dbms/include/DB/Storages/StorageReplicatedMergeTree.h
index 2f91dfa0c3d..ca746fc7173 100644
--- a/dbms/include/DB/Storages/StorageReplicatedMergeTree.h
+++ b/dbms/include/DB/Storages/StorageReplicatedMergeTree.h
@@ -62,6 +62,8 @@ public:
 
 	BlockOutputStreamPtr write(ASTPtr query) override;
 
+	bool optimize() override;
+
 	/** Удаляет реплику из ZooKeeper. Если других реплик нет, удаляет всю таблицу из ZooKeeper.
 	  */
 	void drop() override;
@@ -243,6 +245,7 @@ private:
 	/// Для чтения данных из директории unreplicated.
 	std::unique_ptr<MergeTreeData> unreplicated_data;
 	std::unique_ptr<MergeTreeDataSelectExecutor> unreplicated_reader;
+	std::unique_ptr<MergeTreeDataMerger> unreplicated_merger;
 
 	/// Поток, следящий за обновлениями в логах всех реплик и загружающий их в очередь.
 	std::thread queue_updating_thread;
diff --git a/dbms/src/Storages/StorageReplicatedMergeTree.cpp b/dbms/src/Storages/StorageReplicatedMergeTree.cpp
index ce343be4f2e..b930dea0ff5 100644
--- a/dbms/src/Storages/StorageReplicatedMergeTree.cpp
+++ b/dbms/src/Storages/StorageReplicatedMergeTree.cpp
@@ -70,6 +70,7 @@ StorageReplicatedMergeTree::StorageReplicatedMergeTree(
 			date_column_name_, sampling_expression_, index_granularity_, mode_, sign_column_, settings_,
 			database_name_ + "." + table_name + "[unreplicated]"));
 		unreplicated_reader.reset(new MergeTreeDataSelectExecutor(*unreplicated_data));
+		unreplicated_merger.reset(new MergeTreeDataMerger(*unreplicated_data));
 	}
 }
 
@@ -1027,6 +1028,10 @@ void StorageReplicatedMergeTree::shutdown()
 	replica_is_active_node = nullptr;
 	endpoint_holder = nullptr;
 
+	merger.cancelAll();
+	if (unreplicated_merger)
+		unreplicated_merger->cancelAll();
+
 	LOG_TRACE(log, "Waiting for threads to finish");
 	if (is_leader_node)
 	{
@@ -1098,6 +1103,25 @@ BlockOutputStreamPtr StorageReplicatedMergeTree::write(ASTPtr query)
 	return new ReplicatedMergeTreeBlockOutputStream(*this, insert_id);
 }
 
+bool StorageReplicatedMergeTree::optimize()
+{
+	/// Померджим какие-нибудь куски из директории unreplicated. TODO: Мерджить реплицируемые куски тоже.
+
+	if (!unreplicated_data)
+		return false;
+
+	unreplicated_data->clearOldParts();
+
+	MergeTreeData::DataPartsVector parts;
+	String merged_name;
+	auto always_can_merge = [](const MergeTreeData::DataPartPtr &a, const MergeTreeData::DataPartPtr &b) { return true; };
+	if (!unreplicated_merger->selectPartsToMerge(parts, merged_name, 0, true, true, false, always_can_merge))
+		return false;
+
+	unreplicated_merger->mergeParts(parts, merged_name);
+	return true;
+}
+
 void StorageReplicatedMergeTree::drop()
 {
 	shutdown();