diff --git a/dbms/include/DB/DataStreams/RemoteBlockInputStream.h b/dbms/include/DB/DataStreams/RemoteBlockInputStream.h
index fe9b693f8db..336e836207d 100644
--- a/dbms/include/DB/DataStreams/RemoteBlockInputStream.h
+++ b/dbms/include/DB/DataStreams/RemoteBlockInputStream.h
@@ -29,24 +29,28 @@ private:
 public:
 	/// Принимает готовое соединение.
 	RemoteBlockInputStream(Connection & connection_, const String & query_, const Settings * settings_,
-		const Tables & external_tables_ = Tables(), QueryProcessingStage::Enum stage_ = QueryProcessingStage::Complete)
-		: connection(&connection_), query(query_), external_tables(external_tables_), stage(stage_)
+		const Tables & external_tables_ = Tables(), QueryProcessingStage::Enum stage_ = QueryProcessingStage::Complete,
+		const Context & context = Context{})
+		: connection(&connection_), query(query_), external_tables(external_tables_), stage(stage_), context(context)
 	{
 		init(settings_);
 	}
 
 	/// Принимает готовое соединение. Захватывает владение соединением из пула.
 	RemoteBlockInputStream(ConnectionPool::Entry & pool_entry_, const String & query_, const Settings * settings_,
-		const Tables & external_tables_ = Tables(), QueryProcessingStage::Enum stage_ = QueryProcessingStage::Complete)
-		: pool_entry(pool_entry_), connection(&*pool_entry_), query(query_), external_tables(external_tables_), stage(stage_)
+		const Tables & external_tables_ = Tables(), QueryProcessingStage::Enum stage_ = QueryProcessingStage::Complete,
+		const Context & context = Context{})
+		: pool_entry(pool_entry_), connection(&*pool_entry_), query(query_),
+		  external_tables(external_tables_), stage(stage_), context(context)
 	{
 		init(settings_);
 	}
 
 	/// Принимает пул, из которого нужно будет достать соединение.
 	RemoteBlockInputStream(IConnectionPool * pool_, const String & query_, const Settings * settings_,
-		const Tables & external_tables_ = Tables(), QueryProcessingStage::Enum stage_ = QueryProcessingStage::Complete)
-		: pool(pool_), query(query_), external_tables(external_tables_), stage(stage_)
+		const Tables & external_tables_ = Tables(), QueryProcessingStage::Enum stage_ = QueryProcessingStage::Complete,
+		const Context & context = Context{})
+		: pool(pool_), query(query_), external_tables(external_tables_), stage(stage_), context(context)
 	{
 		init(settings_);
 	}
@@ -103,7 +107,8 @@ protected:
 		{
 			StoragePtr cur = table.second;
 			QueryProcessingStage::Enum stage = QueryProcessingStage::Complete;
-			DB::BlockInputStreams input = cur->read(cur->getColumnNamesList(), ASTPtr(), settings, stage, DEFAULT_BLOCK_SIZE, 1);
+			DB::BlockInputStreams input = cur->read(cur->getColumnNamesList(), ASTPtr(), context, settings,
+				stage, DEFAULT_BLOCK_SIZE, 1);
 			if (input.size() == 0)
 				res.push_back(std::make_pair(new OneBlockInputStream(cur->getSampleBlock()), table.first));
 			else
@@ -246,6 +251,7 @@ private:
 	/// Временные таблицы, которые необходимо переслать на удаленные сервера.
 	Tables external_tables;
 	QueryProcessingStage::Enum stage;
+	Context context;
 
 	/// Отправили запрос (это делается перед получением первого блока).
 	bool sent_query = false;
diff --git a/dbms/include/DB/Storages/IStorage.h b/dbms/include/DB/Storages/IStorage.h
index 7148e0207bc..a4153f165bf 100644
--- a/dbms/include/DB/Storages/IStorage.h
+++ b/dbms/include/DB/Storages/IStorage.h
@@ -162,6 +162,7 @@ public:
 	virtual BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/MergeTree/MergeTreeDataSelectExecutor.h b/dbms/include/DB/Storages/MergeTree/MergeTreeDataSelectExecutor.h
index 89b90025e27..b7f80cd37cd 100644
--- a/dbms/include/DB/Storages/MergeTree/MergeTreeDataSelectExecutor.h
+++ b/dbms/include/DB/Storages/MergeTree/MergeTreeDataSelectExecutor.h
@@ -20,6 +20,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageBuffer.h b/dbms/include/DB/Storages/StorageBuffer.h
index 2eb9a43246c..a15979453c7 100644
--- a/dbms/include/DB/Storages/StorageBuffer.h
+++ b/dbms/include/DB/Storages/StorageBuffer.h
@@ -61,6 +61,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageChunkMerger.h b/dbms/include/DB/Storages/StorageChunkMerger.h
index d3a4fb97a55..c8087c5ebe5 100644
--- a/dbms/include/DB/Storages/StorageChunkMerger.h
+++ b/dbms/include/DB/Storages/StorageChunkMerger.h
@@ -40,6 +40,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageChunkRef.h b/dbms/include/DB/Storages/StorageChunkRef.h
index 3f643d5705a..6f0575e4a2c 100644
--- a/dbms/include/DB/Storages/StorageChunkRef.h
+++ b/dbms/include/DB/Storages/StorageChunkRef.h
@@ -25,6 +25,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageChunks.h b/dbms/include/DB/Storages/StorageChunks.h
index 196b6df98b3..ca07a2611b3 100644
--- a/dbms/include/DB/Storages/StorageChunks.h
+++ b/dbms/include/DB/Storages/StorageChunks.h
@@ -37,6 +37,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
@@ -46,6 +47,7 @@ public:
 		const std::string & chunk_name,
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageDistributed.h b/dbms/include/DB/Storages/StorageDistributed.h
index 1425d99d132..c0c9367f424 100644
--- a/dbms/include/DB/Storages/StorageDistributed.h
+++ b/dbms/include/DB/Storages/StorageDistributed.h
@@ -60,6 +60,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageLog.h b/dbms/include/DB/Storages/StorageLog.h
index 9194d7b7667..e445cf883b8 100644
--- a/dbms/include/DB/Storages/StorageLog.h
+++ b/dbms/include/DB/Storages/StorageLog.h
@@ -162,6 +162,7 @@ public:
 	virtual BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
@@ -227,6 +228,7 @@ protected:
 		size_t to_mark,
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageMaterializedView.h b/dbms/include/DB/Storages/StorageMaterializedView.h
index f4dba33a8bb..23104f8e570 100644
--- a/dbms/include/DB/Storages/StorageMaterializedView.h
+++ b/dbms/include/DB/Storages/StorageMaterializedView.h
@@ -37,6 +37,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageMemory.h b/dbms/include/DB/Storages/StorageMemory.h
index 5c2f8da4831..2fb561c6e6d 100644
--- a/dbms/include/DB/Storages/StorageMemory.h
+++ b/dbms/include/DB/Storages/StorageMemory.h
@@ -83,6 +83,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageMerge.h b/dbms/include/DB/Storages/StorageMerge.h
index b4f14a370b4..5700bd29878 100644
--- a/dbms/include/DB/Storages/StorageMerge.h
+++ b/dbms/include/DB/Storages/StorageMerge.h
@@ -49,6 +49,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageMergeTree.h b/dbms/include/DB/Storages/StorageMergeTree.h
index f1bfb184ccb..a2c4f68ee26 100644
--- a/dbms/include/DB/Storages/StorageMergeTree.h
+++ b/dbms/include/DB/Storages/StorageMergeTree.h
@@ -70,6 +70,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageNull.h b/dbms/include/DB/Storages/StorageNull.h
index cd666deac51..0460ff11096 100644
--- a/dbms/include/DB/Storages/StorageNull.h
+++ b/dbms/include/DB/Storages/StorageNull.h
@@ -33,10 +33,11 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
-		size_t max_block_size = DEFAULT_BLOCK_SIZE,
-		unsigned threads = 1) override
+		const size_t max_block_size = DEFAULT_BLOCK_SIZE,
+		const unsigned threads = 1) override
 	{
 		return { new NullBlockInputStream };
 	}
diff --git a/dbms/include/DB/Storages/StorageReplicatedMergeTree.h b/dbms/include/DB/Storages/StorageReplicatedMergeTree.h
index 6d1f52987fa..3de03cd27e4 100644
--- a/dbms/include/DB/Storages/StorageReplicatedMergeTree.h
+++ b/dbms/include/DB/Storages/StorageReplicatedMergeTree.h
@@ -74,6 +74,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageSystemDatabases.h b/dbms/include/DB/Storages/StorageSystemDatabases.h
index 90bcce9db58..f3a3188e321 100644
--- a/dbms/include/DB/Storages/StorageSystemDatabases.h
+++ b/dbms/include/DB/Storages/StorageSystemDatabases.h
@@ -27,6 +27,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageSystemEvents.h b/dbms/include/DB/Storages/StorageSystemEvents.h
index 4ea4026c8a8..8ce3febbd43 100644
--- a/dbms/include/DB/Storages/StorageSystemEvents.h
+++ b/dbms/include/DB/Storages/StorageSystemEvents.h
@@ -26,6 +26,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageSystemMerges.h b/dbms/include/DB/Storages/StorageSystemMerges.h
index b2dc8e6f82a..b8e365333d5 100644
--- a/dbms/include/DB/Storages/StorageSystemMerges.h
+++ b/dbms/include/DB/Storages/StorageSystemMerges.h
@@ -17,6 +17,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageSystemNumbers.h b/dbms/include/DB/Storages/StorageSystemNumbers.h
index 8ff60f946ae..5de23e6112f 100644
--- a/dbms/include/DB/Storages/StorageSystemNumbers.h
+++ b/dbms/include/DB/Storages/StorageSystemNumbers.h
@@ -28,6 +28,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageSystemOne.h b/dbms/include/DB/Storages/StorageSystemOne.h
index 5a4ba9993bd..2e34e84bb92 100644
--- a/dbms/include/DB/Storages/StorageSystemOne.h
+++ b/dbms/include/DB/Storages/StorageSystemOne.h
@@ -25,6 +25,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageSystemParts.h b/dbms/include/DB/Storages/StorageSystemParts.h
index 4b7a029a443..b9dab8843e1 100644
--- a/dbms/include/DB/Storages/StorageSystemParts.h
+++ b/dbms/include/DB/Storages/StorageSystemParts.h
@@ -27,6 +27,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageSystemProcesses.h b/dbms/include/DB/Storages/StorageSystemProcesses.h
index 8663d2aa781..e7290f2291b 100644
--- a/dbms/include/DB/Storages/StorageSystemProcesses.h
+++ b/dbms/include/DB/Storages/StorageSystemProcesses.h
@@ -27,6 +27,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageSystemReplicas.h b/dbms/include/DB/Storages/StorageSystemReplicas.h
index 631ecfa7b98..b44e77d1790 100644
--- a/dbms/include/DB/Storages/StorageSystemReplicas.h
+++ b/dbms/include/DB/Storages/StorageSystemReplicas.h
@@ -27,6 +27,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageSystemSettings.h b/dbms/include/DB/Storages/StorageSystemSettings.h
index 11e35010e6d..8ee31429fea 100644
--- a/dbms/include/DB/Storages/StorageSystemSettings.h
+++ b/dbms/include/DB/Storages/StorageSystemSettings.h
@@ -27,6 +27,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageSystemTables.h b/dbms/include/DB/Storages/StorageSystemTables.h
index d4b1dee4881..d91788c2a50 100644
--- a/dbms/include/DB/Storages/StorageSystemTables.h
+++ b/dbms/include/DB/Storages/StorageSystemTables.h
@@ -27,6 +27,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageSystemZooKeeper.h b/dbms/include/DB/Storages/StorageSystemZooKeeper.h
index e02a5d19dc3..35c263ec268 100644
--- a/dbms/include/DB/Storages/StorageSystemZooKeeper.h
+++ b/dbms/include/DB/Storages/StorageSystemZooKeeper.h
@@ -27,6 +27,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageTinyLog.h b/dbms/include/DB/Storages/StorageTinyLog.h
index 459a7a8e801..c33278a62fa 100644
--- a/dbms/include/DB/Storages/StorageTinyLog.h
+++ b/dbms/include/DB/Storages/StorageTinyLog.h
@@ -129,6 +129,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/Storages/StorageView.h b/dbms/include/DB/Storages/StorageView.h
index 45d9b58c3dd..f6fcfcddb9b 100644
--- a/dbms/include/DB/Storages/StorageView.h
+++ b/dbms/include/DB/Storages/StorageView.h
@@ -33,6 +33,7 @@ public:
 	BlockInputStreams read(
 		const Names & column_names,
 		ASTPtr query,
+		const Context & context,
 		const Settings & settings,
 		QueryProcessingStage::Enum & processed_stage,
 		size_t max_block_size = DEFAULT_BLOCK_SIZE,
diff --git a/dbms/include/DB/TableFunctions/TableFunctionRemote.h b/dbms/include/DB/TableFunctions/TableFunctionRemote.h
index 400a0a24ec5..a48ab1c0be4 100644
--- a/dbms/include/DB/TableFunctions/TableFunctionRemote.h
+++ b/dbms/include/DB/TableFunctions/TableFunctionRemote.h
@@ -90,7 +90,12 @@ private:
 		NamesAndTypesList res;
 
 		/// Отправляем на первый попавшийся шард
-		BlockInputStreamPtr input = new RemoteBlockInputStream(&*cluster.pools.front(), query, &settings, Tables(), QueryProcessingStage::Complete);
+		BlockInputStreamPtr input{
+			new RemoteBlockInputStream{
+				cluster.pools.front().get(), query, &settings,
+				Tables(), QueryProcessingStage::Complete, context
+			}
+		};
 		input->readPrefix();
 
 		while (true)
diff --git a/dbms/src/Interpreters/ExpressionAnalyzer.cpp b/dbms/src/Interpreters/ExpressionAnalyzer.cpp
index 0bc06dcbd3c..dd86b5c9682 100644
--- a/dbms/src/Interpreters/ExpressionAnalyzer.cpp
+++ b/dbms/src/Interpreters/ExpressionAnalyzer.cpp
@@ -32,6 +32,8 @@
 
 #include <DB/Parsers/formatAST.h>
 
+#include <statdaemons/ext/range.hpp>
+
 
 namespace DB
 {
@@ -589,6 +591,9 @@ static SharedPtr<InterpreterSelectQuery> interpretSubquery(
 		if (!parse_res)
 			throw Exception("Error in parsing SELECT query while creating set or join for table " + table->name + ".",
 				ErrorCodes::LOGICAL_ERROR);
+
+		/// @note it may be more appropriate to manually replace ASTAsterisk with table's columns
+		ExpressionAnalyzer{query, context, subquery_depth};
 	}
 	else
 		query = subquery->children.at(0);
@@ -1737,26 +1742,32 @@ void ExpressionAnalyzer::collectJoinedColumns(NameSet & joined_columns, NamesAnd
 		return;
 
 	auto & node = typeid_cast<ASTJoin &>(*select_query->join);
-	auto & keys = typeid_cast<ASTExpressionList &>(*node.using_expr_list);
-	auto & table = node.table->children.at(0);		/// TODO: поддержка идентификаторов.
 
-	size_t num_join_keys = keys.children.size();
-
-	for (size_t i = 0; i < num_join_keys; ++i)
+	Block nested_result_sample;
+	if (const auto identifier = typeid_cast<const ASTIdentifier *>(node.table.get()))
 	{
-		if (!join_key_names_left_set.insert(keys.children[i]->getColumnName()).second)
+		const auto & table = context.getTable("", identifier->name);
+		nested_result_sample = table->getSampleBlockNonMaterialized();
+	}
+	else if (typeid_cast<const ASTSubquery *>(node.table.get()))
+	{
+		const auto & table = node.table->children.at(0);
+		nested_result_sample = ExpressionAnalyzer(table, context, subquery_depth + 1).getSelectSampleBlock();	
+	}
+
+	auto & keys = typeid_cast<ASTExpressionList &>(*node.using_expr_list);
+	for (const auto & key : keys.children)
+	{
+		if (!join_key_names_left_set.insert(key->getColumnName()).second)
 			throw Exception("Duplicate column in USING list", ErrorCodes::DUPLICATE_COLUMN);
 
-		if (!join_key_names_right_set.insert(keys.children[i]->getAliasOrColumnName()).second)
+		if (!join_key_names_right_set.insert(key->getAliasOrColumnName()).second)
 			throw Exception("Duplicate column in USING list", ErrorCodes::DUPLICATE_COLUMN);
 	}
 
-	Block nested_result_sample = ExpressionAnalyzer(table, context, subquery_depth + 1).getSelectSampleBlock();
-
-	size_t nested_result_columns = nested_result_sample.columns();
-	for (size_t i = 0; i < nested_result_columns; ++i)
+	for (const auto i : ext::range(0, nested_result_sample.columns()))
 	{
-		auto col = nested_result_sample.getByPosition(i);
+		const auto & col = nested_result_sample.getByPosition(i);
 		if (!join_key_names_right_set.count(col.name))
 		{
 			joined_columns.insert(col.name);
diff --git a/dbms/src/Interpreters/InterpreterSelectQuery.cpp b/dbms/src/Interpreters/InterpreterSelectQuery.cpp
index 677014fa014..538879e0d0c 100644
--- a/dbms/src/Interpreters/InterpreterSelectQuery.cpp
+++ b/dbms/src/Interpreters/InterpreterSelectQuery.cpp
@@ -547,7 +547,9 @@ QueryProcessingStage::Enum InterpreterSelectQuery::executeFetchColumns(BlockInpu
 		if (storage && storage->isRemote())
 			storage->storeExternalTables(query_analyzer->getExternalTables());
 
-		streams = storage->read(required_columns, query_ptr, settings_for_storage, from_stage, settings.max_block_size, settings.max_threads);
+		streams = storage->read(required_columns, query_ptr,
+								context, settings_for_storage, from_stage,
+								settings.max_block_size, settings.max_threads);
 
 		for (auto & stream : streams)
 			stream->addTableLock(table_lock);
diff --git a/dbms/src/Storages/MergeTree/MergeTreeDataSelectExecutor.cpp b/dbms/src/Storages/MergeTree/MergeTreeDataSelectExecutor.cpp
index 16f88703115..e2367f44dcb 100644
--- a/dbms/src/Storages/MergeTree/MergeTreeDataSelectExecutor.cpp
+++ b/dbms/src/Storages/MergeTree/MergeTreeDataSelectExecutor.cpp
@@ -38,10 +38,11 @@ static Block getBlockWithVirtualColumns(const MergeTreeData::DataPartsVector & p
 BlockInputStreams MergeTreeDataSelectExecutor::read(
 	const Names & column_names_to_return,
 	ASTPtr query,
+	const Context & context,
 	const Settings & settings,
 	QueryProcessingStage::Enum & processed_stage,
-	size_t max_block_size,
-	unsigned threads,
+	const size_t max_block_size,
+	const unsigned threads,
 	size_t * part_index)
 {
 	size_t part_index_var = 0;
@@ -74,15 +75,15 @@ BlockInputStreams MergeTreeDataSelectExecutor::read(
 
 	/// Если запрошен хотя бы один виртуальный столбец, пробуем индексировать
 	if (!virt_column_names.empty())
-		VirtualColumnUtils::filterBlockWithQuery(query, virtual_columns_block, data.context);
+		VirtualColumnUtils::filterBlockWithQuery(query, virtual_columns_block, context);
 
 	std::multiset<String> values = VirtualColumnUtils::extractSingleValueFromBlock<String>(virtual_columns_block, "_part");
 
 	data.check(real_column_names);
 	processed_stage = QueryProcessingStage::FetchColumns;
 
-	PKCondition key_condition(query, data.context, data.getColumnsList(), data.getSortDescription());
-	PKCondition date_condition(query, data.context, data.getColumnsList(), SortDescription(1, SortColumnDescription(data.date_column_name, 1)));
+	PKCondition key_condition(query, context, data.getColumnsList(), data.getSortDescription());
+	PKCondition date_condition(query, context, data.getColumnsList(), SortDescription(1, SortColumnDescription(data.date_column_name, 1)));
 
 	/// Выберем куски, в которых могут быть данные, удовлетворяющие date_condition, и которые подходят под условие на _part.
 	{
diff --git a/dbms/src/Storages/StorageBuffer.cpp b/dbms/src/Storages/StorageBuffer.cpp
index 499976b0ca4..9bf472ad63a 100644
--- a/dbms/src/Storages/StorageBuffer.cpp
+++ b/dbms/src/Storages/StorageBuffer.cpp
@@ -90,6 +90,7 @@ private:
 BlockInputStreams StorageBuffer::read(
 	const Names & column_names,
 	ASTPtr query,
+	const Context & context,
 	const Settings & settings,
 	QueryProcessingStage::Enum & processed_stage,
 	size_t max_block_size,
@@ -101,7 +102,7 @@ BlockInputStreams StorageBuffer::read(
 
 	if (!no_destination)
 		streams_from_dst = context.getTable(destination_database, destination_table)->read(
-			column_names, query, settings, processed_stage, max_block_size, threads);
+			column_names, query, context, settings, processed_stage, max_block_size, threads);
 
 	BlockInputStreams streams_from_buffers;
 	streams_from_buffers.reserve(num_shards);
diff --git a/dbms/src/Storages/StorageChunkMerger.cpp b/dbms/src/Storages/StorageChunkMerger.cpp
index 72faaa8a4cd..7462efa9f20 100644
--- a/dbms/src/Storages/StorageChunkMerger.cpp
+++ b/dbms/src/Storages/StorageChunkMerger.cpp
@@ -62,10 +62,11 @@ bool StorageChunkMerger::hasColumn(const String & column_name) const
 BlockInputStreams StorageChunkMerger::read(
 	const Names & column_names,
 	ASTPtr query,
+	const Context & context,
 	const Settings & settings,
 	QueryProcessingStage::Enum & processed_stage,
-	size_t max_block_size,
-	unsigned threads)
+	const size_t max_block_size,
+	const unsigned threads)
 {
 	/// Будем читать из таблиц Chunks, на которые есть хоть одна ChunkRef, подходящая под регэксп, и из прочих таблиц, подходящих под регэксп.
 	Storages selected_tables;
@@ -76,16 +77,17 @@ BlockInputStreams StorageChunkMerger::read(
 		typedef std::set<std::string> StringSet;
 		StringSet chunks_table_names;
 
-		Databases & databases = context.getDatabases();
+		const Databases & databases = context.getDatabases();
 
-		if (!databases.count(source_database))
+		const auto database_it = databases.find(source_database);
+		if (database_it == std::end(databases))
 			throw Exception("No database " + source_database, ErrorCodes::UNKNOWN_DATABASE);
 
-		Tables & tables = databases[source_database];
-		for (Tables::iterator it = tables.begin(); it != tables.end(); ++it)
+		const Tables & tables = database_it->second;
+		for (const auto & it : tables)
 		{
-			StoragePtr table = it->second;
-			if (table_name_regexp.match(it->first) &&
+			const StoragePtr & table = it.second;
+			if (table_name_regexp.match(it.first) &&
 				!typeid_cast<StorageChunks *>(&*table) &&
 				!typeid_cast<StorageChunkMerger *>(&*table))
 			{
@@ -93,19 +95,20 @@ BlockInputStreams StorageChunkMerger::read(
 				{
 					if (chunk_ref->source_database_name != source_database)
 					{
-						LOG_WARNING(log, "ChunkRef " + it->first + " points to another database, ignoring");
+						LOG_WARNING(log, "ChunkRef " + it.first + " points to another database, ignoring");
 						continue;
 					}
 					if (!chunks_table_names.count(chunk_ref->source_table_name))
 					{
-						if (tables.count(chunk_ref->source_table_name))
+						const auto table_it = tables.find(chunk_ref->source_table_name);
+						if (table_it != std::end(tables))
 						{
 							chunks_table_names.insert(chunk_ref->source_table_name);
-							selected_tables.push_back(tables[chunk_ref->source_table_name]);
+							selected_tables.push_back(table_it->second);
 						}
 						else
 						{
-							LOG_WARNING(log, "ChunkRef " + it->first + " points to non-existing Chunks table, ignoring");
+							LOG_WARNING(log, "ChunkRef " + it.first + " points to non-existing Chunks table, ignoring");
 						}
 					}
 				}
@@ -174,6 +177,7 @@ BlockInputStreams StorageChunkMerger::read(
 		BlockInputStreams source_streams = table->read(
 			real_column_names,
 			modified_query_ast,
+			context,
 			settings,
 			tmp_processed_stage,
 			max_block_size,
@@ -465,6 +469,7 @@ bool StorageChunkMerger::mergeChunks(const Storages & chunks)
 			BlockInputStreams input_streams = src_storage->read(
 				src_column_names,
 				select_query_ptr,
+				context,
 				settings,
 				processed_stage,
 				DEFAULT_MERGE_BLOCK_SIZE);
diff --git a/dbms/src/Storages/StorageChunkRef.cpp b/dbms/src/Storages/StorageChunkRef.cpp
index f84ff574773..377b633e879 100644
--- a/dbms/src/Storages/StorageChunkRef.cpp
+++ b/dbms/src/Storages/StorageChunkRef.cpp
@@ -12,14 +12,17 @@ StoragePtr StorageChunkRef::create(const std::string & name_, const Context & co
 }
 
 BlockInputStreams StorageChunkRef::read(
-		const Names & column_names,
-		ASTPtr query,
-		const Settings & settings,
-		QueryProcessingStage::Enum & processed_stage,
-		size_t max_block_size,
-		unsigned threads)
+	const Names & column_names,
+	ASTPtr query,
+	const Context & context,
+	const Settings & settings,
+	QueryProcessingStage::Enum & processed_stage,
+	const size_t max_block_size,
+	const unsigned threads)
 {
-	return getSource().readFromChunk(name, column_names, query, settings, processed_stage, max_block_size, threads);
+	return getSource().readFromChunk(name, column_names, query,
+									 context, settings, processed_stage,
+									 max_block_size, threads);
 }
 
 ASTPtr StorageChunkRef::getCustomCreateQuery(const Context & context) const
diff --git a/dbms/src/Storages/StorageChunks.cpp b/dbms/src/Storages/StorageChunks.cpp
index 9b6fb81cee3..c3aad961a39 100644
--- a/dbms/src/Storages/StorageChunks.cpp
+++ b/dbms/src/Storages/StorageChunks.cpp
@@ -46,10 +46,11 @@ void StorageChunks::removeReference()
 BlockInputStreams StorageChunks::read(
 	const Names & column_names,
 	ASTPtr query,
+	const Context & context,
 	const Settings & settings,
 	QueryProcessingStage::Enum & processed_stage,
-	size_t max_block_size,
-	unsigned threads)
+	const size_t max_block_size,
+	const unsigned threads)
 {
 	bool has_virtual_column = false;
 
@@ -59,17 +60,21 @@ BlockInputStreams StorageChunks::read(
 
 	/// Если виртуальных столбцов нет, просто считать данные из таблицы
 	if (!has_virtual_column)
-		return read(0, std::numeric_limits<size_t>::max(), column_names, query, settings, processed_stage, max_block_size, threads);
+		return read(0, std::numeric_limits<size_t>::max(), column_names,
+					query, context, settings,
+					processed_stage, max_block_size, threads);
 
 	Block virtual_columns_block = getBlockWithVirtualColumns();
 	if (!VirtualColumnUtils::filterBlockWithQuery(query, virtual_columns_block, context))
-		return read(0, std::numeric_limits<size_t>::max(), column_names, query, settings, processed_stage, max_block_size, threads);
+		return read(0, std::numeric_limits<size_t>::max(), column_names,
+					query, context, settings,
+					processed_stage, max_block_size, threads);
 	std::multiset<String> values = VirtualColumnUtils::extractSingleValueFromBlock<String>(virtual_columns_block, _table_column_name);
 
 	BlockInputStreams res;
 	for (const auto & it : values)
 	{
-		BlockInputStreams temp = readFromChunk(it, column_names, query, settings, processed_stage, max_block_size, threads);
+		BlockInputStreams temp = readFromChunk(it, column_names, query, context, settings, processed_stage, max_block_size, threads);
 		res.insert(res.end(), temp.begin(), temp.end());
 	}
 	return res;
@@ -92,10 +97,11 @@ BlockInputStreams StorageChunks::readFromChunk(
 	const std::string & chunk_name,
 	const Names & column_names,
 	ASTPtr query,
+	const Context & context,
 	const Settings & settings,
 	QueryProcessingStage::Enum & processed_stage,
-	size_t max_block_size,
-	unsigned threads)
+	const size_t max_block_size,
+	const unsigned threads)
 {
 	size_t mark1;
 	size_t mark2;
@@ -110,7 +116,7 @@ BlockInputStreams StorageChunks::readFromChunk(
 		mark2 = index + 1 == chunk_num_to_marks.size() ? marksCount() : chunk_num_to_marks[index + 1];
 	}
 
-	return read(mark1, mark2, column_names, query, settings, processed_stage, max_block_size, threads);
+	return read(mark1, mark2, column_names, query, context, settings, processed_stage, max_block_size, threads);
 }
 
 BlockOutputStreamPtr StorageChunks::writeToNewChunk(
diff --git a/dbms/src/Storages/StorageDistributed.cpp b/dbms/src/Storages/StorageDistributed.cpp
index 25f339f34cb..ce38efef02b 100644
--- a/dbms/src/Storages/StorageDistributed.cpp
+++ b/dbms/src/Storages/StorageDistributed.cpp
@@ -140,10 +140,11 @@ StoragePtr StorageDistributed::create(
 BlockInputStreams StorageDistributed::read(
 	const Names & column_names,
 	ASTPtr query,
+	const Context & context,
 	const Settings & settings,
 	QueryProcessingStage::Enum & processed_stage,
-	size_t max_block_size,
-	unsigned threads)
+	const size_t max_block_size,
+	const unsigned threads)
 {
 	Settings new_settings = settings;
 	new_settings.queue_max_wait_ms = Cluster::saturate(new_settings.queue_max_wait_ms, settings.limits.max_execution_time);
@@ -163,7 +164,8 @@ BlockInputStreams StorageDistributed::read(
 	for (auto & conn_pool : cluster.pools)
 		res.emplace_back(new RemoteBlockInputStream{
 			conn_pool, modified_query, &new_settings,
-			external_tables, processed_stage});
+			external_tables, processed_stage, context
+		});
 
 	/// Добавляем запросы к локальному ClickHouse.
 	if (cluster.getLocalNodesNum() > 0)
diff --git a/dbms/src/Storages/StorageLog.cpp b/dbms/src/Storages/StorageLog.cpp
index e980e9055a5..28cfce37b55 100644
--- a/dbms/src/Storages/StorageLog.cpp
+++ b/dbms/src/Storages/StorageLog.cpp
@@ -620,6 +620,7 @@ BlockInputStreams StorageLog::read(
 	size_t to_mark,
 	const Names & column_names,
 	ASTPtr query,
+	const Context & context,
 	const Settings & settings,
 	QueryProcessingStage::Enum & processed_stage,
 	size_t max_block_size,
@@ -693,12 +694,15 @@ BlockInputStreams StorageLog::read(
 BlockInputStreams StorageLog::read(
 	const Names & column_names,
 	ASTPtr query,
+	const Context & context,
 	const Settings & settings,
 	QueryProcessingStage::Enum & processed_stage,
-	size_t max_block_size,
-	unsigned threads)
+	const size_t max_block_size,
+	const unsigned threads)
 {
-	return read(0, std::numeric_limits<size_t>::max(), column_names, query, settings, processed_stage, max_block_size, threads);
+	return read(0, std::numeric_limits<size_t>::max(), column_names,
+				query, context, settings, processed_stage,
+				max_block_size, threads);
 }
 
 
diff --git a/dbms/src/Storages/StorageMaterializedView.cpp b/dbms/src/Storages/StorageMaterializedView.cpp
index a9560808b1d..e9e84d541b4 100644
--- a/dbms/src/Storages/StorageMaterializedView.cpp
+++ b/dbms/src/Storages/StorageMaterializedView.cpp
@@ -99,12 +99,13 @@ bool StorageMaterializedView::hasColumn(const String & column_name) const
 BlockInputStreams StorageMaterializedView::read(
 	const Names & column_names,
 	ASTPtr query,
+	const Context & context,
 	const Settings & settings,
 	QueryProcessingStage::Enum & processed_stage,
-	size_t max_block_size,
-	unsigned threads)
+	const size_t max_block_size,
+	const unsigned threads)
 {
-	return data->read(column_names, query, settings, processed_stage, max_block_size, threads);
+	return data->read(column_names, query, context, settings, processed_stage, max_block_size, threads);
 }
 
 BlockOutputStreamPtr StorageMaterializedView::write(ASTPtr query)
diff --git a/dbms/src/Storages/StorageMemory.cpp b/dbms/src/Storages/StorageMemory.cpp
index b5ba1dac28d..b22f1080a2c 100644
--- a/dbms/src/Storages/StorageMemory.cpp
+++ b/dbms/src/Storages/StorageMemory.cpp
@@ -99,6 +99,7 @@ StoragePtr StorageMemory::create(
 BlockInputStreams StorageMemory::read(
 	const Names & column_names,
 	ASTPtr query,
+	const Context & context,
 	const Settings & settings,
 	QueryProcessingStage::Enum & processed_stage,
 	size_t max_block_size,
diff --git a/dbms/src/Storages/StorageMerge.cpp b/dbms/src/Storages/StorageMerge.cpp
index aaa169f4688..fcb99636408 100644
--- a/dbms/src/Storages/StorageMerge.cpp
+++ b/dbms/src/Storages/StorageMerge.cpp
@@ -79,10 +79,11 @@ bool StorageMerge::hasColumn(const String & column_name) const
 BlockInputStreams StorageMerge::read(
 	const Names & column_names,
 	ASTPtr query,
+	const Context & context,
 	const Settings & settings,
 	QueryProcessingStage::Enum & processed_stage,
-	size_t max_block_size,
-	unsigned threads)
+	const size_t max_block_size,
+	const unsigned threads)
 {
 	BlockInputStreams res;
 
@@ -143,6 +144,7 @@ BlockInputStreams StorageMerge::read(
 		BlockInputStreams source_streams = table->read(
 			real_column_names,
 			modified_query_ast,
+			context,
 			settings,
 			tmp_processed_stage,
 			max_block_size,
diff --git a/dbms/src/Storages/StorageMergeTree.cpp b/dbms/src/Storages/StorageMergeTree.cpp
index 202580c2ac8..bfad370a64d 100644
--- a/dbms/src/Storages/StorageMergeTree.cpp
+++ b/dbms/src/Storages/StorageMergeTree.cpp
@@ -90,12 +90,13 @@ StorageMergeTree::~StorageMergeTree()
 BlockInputStreams StorageMergeTree::read(
 	const Names & column_names,
 	ASTPtr query,
+	const Context & context,
 	const Settings & settings,
 	QueryProcessingStage::Enum & processed_stage,
-	size_t max_block_size,
-	unsigned threads)
+	const size_t max_block_size,
+	const unsigned threads)
 {
-	return reader.read(column_names, query, settings, processed_stage, max_block_size, threads);
+	return reader.read(column_names, query, context, settings, processed_stage, max_block_size, threads);
 }
 
 BlockOutputStreamPtr StorageMergeTree::write(ASTPtr query)
diff --git a/dbms/src/Storages/StorageReplicatedMergeTree.cpp b/dbms/src/Storages/StorageReplicatedMergeTree.cpp
index bbf364bf6a4..f557f9ae7c5 100644
--- a/dbms/src/Storages/StorageReplicatedMergeTree.cpp
+++ b/dbms/src/Storages/StorageReplicatedMergeTree.cpp
@@ -1990,12 +1990,13 @@ StorageReplicatedMergeTree::~StorageReplicatedMergeTree()
 
 
 BlockInputStreams StorageReplicatedMergeTree::read(
-		const Names & column_names,
-		ASTPtr query,
-		const Settings & settings,
-		QueryProcessingStage::Enum & processed_stage,
-		size_t max_block_size,
-		unsigned threads)
+	const Names & column_names,
+	ASTPtr query,
+	const Context & context,
+	const Settings & settings,
+	QueryProcessingStage::Enum & processed_stage,
+	const size_t max_block_size,
+	const unsigned threads)
 {
 	Names virt_column_names;
 	Names real_column_names;
@@ -2024,8 +2025,9 @@ BlockInputStreams StorageReplicatedMergeTree::read(
 
 	if (unreplicated_reader && values.count(0))
 	{
-		res = unreplicated_reader->read(
-			real_column_names, query, settings, processed_stage, max_block_size, threads, &part_index);
+		res = unreplicated_reader->read(real_column_names, query,
+										context, settings, processed_stage,
+										max_block_size, threads, &part_index);
 
 		for (auto & virtual_column : virt_column_names)
 		{
@@ -2039,7 +2041,7 @@ BlockInputStreams StorageReplicatedMergeTree::read(
 
 	if (values.count(1))
 	{
-		auto res2 = reader.read(real_column_names, query, settings, processed_stage, max_block_size, threads, &part_index);
+		auto res2 = reader.read(real_column_names, query, context, settings, processed_stage, max_block_size, threads, &part_index);
 
 		for (auto & virtual_column : virt_column_names)
 		{
diff --git a/dbms/src/Storages/StorageSystemDatabases.cpp b/dbms/src/Storages/StorageSystemDatabases.cpp
index 0a27756a1a1..2e45ed4b355 100644
--- a/dbms/src/Storages/StorageSystemDatabases.cpp
+++ b/dbms/src/Storages/StorageSystemDatabases.cpp
@@ -21,8 +21,13 @@ StoragePtr StorageSystemDatabases::create(const std::string & name_, const Conte
 
 
 BlockInputStreams StorageSystemDatabases::read(
-	const Names & column_names, ASTPtr query, const Settings & settings,
-	QueryProcessingStage::Enum & processed_stage, size_t max_block_size, unsigned threads)
+	const Names & column_names,
+	ASTPtr query,
+	const Context & context,
+	const Settings & settings,
+	QueryProcessingStage::Enum & processed_stage,
+	const size_t max_block_size,
+	const unsigned threads)
 {
 	check(column_names);
 	processed_stage = QueryProcessingStage::FetchColumns;
diff --git a/dbms/src/Storages/StorageSystemEvents.cpp b/dbms/src/Storages/StorageSystemEvents.cpp
index da6e1180348..4b90e3ae4bc 100644
--- a/dbms/src/Storages/StorageSystemEvents.cpp
+++ b/dbms/src/Storages/StorageSystemEvents.cpp
@@ -24,8 +24,13 @@ StoragePtr StorageSystemEvents::create(const std::string & name_)
 
 
 BlockInputStreams StorageSystemEvents::read(
-	const Names & column_names, ASTPtr query, const Settings & settings,
-	QueryProcessingStage::Enum & processed_stage, size_t max_block_size, unsigned threads)
+	const Names & column_names,
+	ASTPtr query,
+	const Context & context,
+	const Settings & settings,
+	QueryProcessingStage::Enum & processed_stage,
+	const size_t max_block_size,
+	const unsigned threads)
 {
 	check(column_names);
 	processed_stage = QueryProcessingStage::FetchColumns;
diff --git a/dbms/src/Storages/StorageSystemMerges.cpp b/dbms/src/Storages/StorageSystemMerges.cpp
index a7de97573b9..8f8fa227173 100644
--- a/dbms/src/Storages/StorageSystemMerges.cpp
+++ b/dbms/src/Storages/StorageSystemMerges.cpp
@@ -33,8 +33,13 @@ StoragePtr StorageSystemMerges::create(const std::string & name, const Context &
 }
 
 BlockInputStreams StorageSystemMerges::read(
-	const Names & column_names, ASTPtr query, const Settings & settings,
-	QueryProcessingStage::Enum & processed_stage, const size_t max_block_size, const unsigned)
+	const Names & column_names,
+	ASTPtr query,
+	const Context & context,
+	const Settings & settings,
+	QueryProcessingStage::Enum & processed_stage,
+	const size_t max_block_size,
+	const unsigned)
 {
 	check(column_names);
 	processed_stage = QueryProcessingStage::FetchColumns;
diff --git a/dbms/src/Storages/StorageSystemNumbers.cpp b/dbms/src/Storages/StorageSystemNumbers.cpp
index 211a57f3d95..ae370669c46 100644
--- a/dbms/src/Storages/StorageSystemNumbers.cpp
+++ b/dbms/src/Storages/StorageSystemNumbers.cpp
@@ -66,8 +66,13 @@ StoragePtr StorageSystemNumbers::create(const std::string & name_, bool multithr
 
 
 BlockInputStreams StorageSystemNumbers::read(
-	const Names & column_names, ASTPtr query, const Settings & settings,
-	QueryProcessingStage::Enum & processed_stage, size_t max_block_size, unsigned threads)
+	const Names & column_names,
+	ASTPtr query,
+	const Context & context,
+	const Settings & settings,
+	QueryProcessingStage::Enum & processed_stage,
+	const size_t max_block_size,
+	unsigned threads)
 {
 	check(column_names);
 	processed_stage = QueryProcessingStage::FetchColumns;
diff --git a/dbms/src/Storages/StorageSystemOne.cpp b/dbms/src/Storages/StorageSystemOne.cpp
index a6d66fed732..c5f0459d71b 100644
--- a/dbms/src/Storages/StorageSystemOne.cpp
+++ b/dbms/src/Storages/StorageSystemOne.cpp
@@ -24,8 +24,13 @@ StoragePtr StorageSystemOne::create(const std::string & name_)
 
 
 BlockInputStreams StorageSystemOne::read(
-	const Names & column_names, ASTPtr query, const Settings & settings,
-	QueryProcessingStage::Enum & processed_stage, size_t max_block_size, unsigned threads)
+	const Names & column_names,
+	ASTPtr query,
+	const Context & context,
+	const Settings & settings,
+	QueryProcessingStage::Enum & processed_stage,
+	const size_t max_block_size,
+	const unsigned threads)
 {
 	check(column_names);
 	processed_stage = QueryProcessingStage::FetchColumns;
diff --git a/dbms/src/Storages/StorageSystemParts.cpp b/dbms/src/Storages/StorageSystemParts.cpp
index c9d7b54a99e..4024fd7aea8 100644
--- a/dbms/src/Storages/StorageSystemParts.cpp
+++ b/dbms/src/Storages/StorageSystemParts.cpp
@@ -38,8 +38,13 @@ StoragePtr StorageSystemParts::create(const std::string & name_, const Context &
 
 
 BlockInputStreams StorageSystemParts::read(
-	const Names & column_names, ASTPtr query, const Settings & settings,
-	QueryProcessingStage::Enum & processed_stage, size_t max_block_size, unsigned threads)
+	const Names & column_names,
+	ASTPtr query,
+	const Context & context,
+	const Settings & settings,
+	QueryProcessingStage::Enum & processed_stage,
+	const size_t max_block_size,
+	const unsigned threads)
 {
 	check(column_names);
 	processed_stage = QueryProcessingStage::FetchColumns;
diff --git a/dbms/src/Storages/StorageSystemProcesses.cpp b/dbms/src/Storages/StorageSystemProcesses.cpp
index e9a92de1572..63f433afe13 100644
--- a/dbms/src/Storages/StorageSystemProcesses.cpp
+++ b/dbms/src/Storages/StorageSystemProcesses.cpp
@@ -32,8 +32,13 @@ StoragePtr StorageSystemProcesses::create(const std::string & name_, const Conte
 
 
 BlockInputStreams StorageSystemProcesses::read(
-	const Names & column_names, ASTPtr query, const Settings & settings,
-	QueryProcessingStage::Enum & processed_stage, size_t max_block_size, unsigned threads)
+	const Names & column_names,
+	ASTPtr query,
+	const Context & context,
+	const Settings & settings,
+	QueryProcessingStage::Enum & processed_stage,
+	const size_t max_block_size,
+	const unsigned threads)
 {
 	check(column_names);
 	processed_stage = QueryProcessingStage::FetchColumns;
diff --git a/dbms/src/Storages/StorageSystemReplicas.cpp b/dbms/src/Storages/StorageSystemReplicas.cpp
index 452fac9eb65..6ef40a9ebfa 100644
--- a/dbms/src/Storages/StorageSystemReplicas.cpp
+++ b/dbms/src/Storages/StorageSystemReplicas.cpp
@@ -46,8 +46,13 @@ StoragePtr StorageSystemReplicas::create(const std::string & name_, const Contex
 
 
 BlockInputStreams StorageSystemReplicas::read(
-	const Names & column_names, ASTPtr query, const Settings & settings,
-	QueryProcessingStage::Enum & processed_stage, size_t max_block_size, unsigned threads)
+	const Names & column_names,
+	ASTPtr query,
+	const Context & context,
+	const Settings & settings,
+	QueryProcessingStage::Enum & processed_stage,
+	const size_t max_block_size,
+	const unsigned threads)
 {
 	check(column_names);
 	processed_stage = QueryProcessingStage::FetchColumns;
@@ -59,7 +64,7 @@ BlockInputStreams StorageSystemReplicas::read(
 
 		for (const auto & db : context.getDatabases())
 			for (const auto & table : db.second)
-				if (typeid_cast<const StorageReplicatedMergeTree *>(&*table.second))
+				if (typeid_cast<const StorageReplicatedMergeTree *>(table.second.get()))
 					replicated_tables[db.first][table.first] = table.second;
 	}
 
diff --git a/dbms/src/Storages/StorageSystemSettings.cpp b/dbms/src/Storages/StorageSystemSettings.cpp
index 0e79044b292..73544d71354 100644
--- a/dbms/src/Storages/StorageSystemSettings.cpp
+++ b/dbms/src/Storages/StorageSystemSettings.cpp
@@ -26,8 +26,13 @@ StoragePtr StorageSystemSettings::create(const std::string & name_, const Contex
 
 
 BlockInputStreams StorageSystemSettings::read(
-	const Names & column_names, ASTPtr query, const Settings & settings,
-	QueryProcessingStage::Enum & processed_stage, size_t max_block_size, unsigned threads)
+	const Names & column_names,
+	ASTPtr query,
+	const Context & context,
+	const Settings & settings,
+	QueryProcessingStage::Enum & processed_stage,
+	const size_t max_block_size,
+	const unsigned threads)
 {
 	check(column_names);
 	processed_stage = QueryProcessingStage::FetchColumns;
diff --git a/dbms/src/Storages/StorageSystemTables.cpp b/dbms/src/Storages/StorageSystemTables.cpp
index e62fa17a256..f35575788ae 100644
--- a/dbms/src/Storages/StorageSystemTables.cpp
+++ b/dbms/src/Storages/StorageSystemTables.cpp
@@ -24,8 +24,13 @@ StoragePtr StorageSystemTables::create(const std::string & name_, const Context
 
 
 BlockInputStreams StorageSystemTables::read(
-	const Names & column_names, ASTPtr query, const Settings & settings,
-	QueryProcessingStage::Enum & processed_stage, size_t max_block_size, unsigned threads)
+	const Names & column_names,
+	ASTPtr query,
+	const Context & context,
+	const Settings & settings,
+	QueryProcessingStage::Enum & processed_stage,
+	const size_t max_block_size,
+	const unsigned threads)
 {
 	check(column_names);
 	processed_stage = QueryProcessingStage::FetchColumns;
diff --git a/dbms/src/Storages/StorageSystemZooKeeper.cpp b/dbms/src/Storages/StorageSystemZooKeeper.cpp
index 2715d490406..ee2d7f9298d 100644
--- a/dbms/src/Storages/StorageSystemZooKeeper.cpp
+++ b/dbms/src/Storages/StorageSystemZooKeeper.cpp
@@ -103,8 +103,13 @@ static String extractPath(const ASTPtr & query)
 
 
 BlockInputStreams StorageSystemZooKeeper::read(
-	const Names & column_names, ASTPtr query, const Settings & settings,
-	QueryProcessingStage::Enum & processed_stage, size_t max_block_size, unsigned threads)
+	const Names & column_names,
+	ASTPtr query,
+	const Context & context,
+	const Settings & settings,
+	QueryProcessingStage::Enum & processed_stage,
+	const size_t max_block_size,
+	const unsigned threads)
 {
 	check(column_names);
 	processed_stage = QueryProcessingStage::FetchColumns;
diff --git a/dbms/src/Storages/StorageTinyLog.cpp b/dbms/src/Storages/StorageTinyLog.cpp
index 3d111c7d8e4..b63f5dd904a 100644
--- a/dbms/src/Storages/StorageTinyLog.cpp
+++ b/dbms/src/Storages/StorageTinyLog.cpp
@@ -406,10 +406,11 @@ void StorageTinyLog::rename(const String & new_path_to_db, const String & new_da
 BlockInputStreams StorageTinyLog::read(
 	const Names & column_names,
 	ASTPtr query,
+	const Context & context,
 	const Settings & settings,
 	QueryProcessingStage::Enum & processed_stage,
-	size_t max_block_size,
-	unsigned threads)
+	const size_t max_block_size,
+	const unsigned threads)
 {
 	check(column_names);
 	processed_stage = QueryProcessingStage::FetchColumns;
diff --git a/dbms/src/Storages/StorageView.cpp b/dbms/src/Storages/StorageView.cpp
index d8a75a3a5bf..50b00df5832 100644
--- a/dbms/src/Storages/StorageView.cpp
+++ b/dbms/src/Storages/StorageView.cpp
@@ -74,10 +74,11 @@ StorageView::StorageView(
 BlockInputStreams StorageView::read(
 	const Names & column_names,
 	ASTPtr query,
+	const Context & context,
 	const Settings & settings,
 	QueryProcessingStage::Enum & processed_stage,
-	size_t max_block_size,
-	unsigned threads)
+	const size_t max_block_size,
+	const unsigned threads)
 {
 	ASTPtr inner_query_clone = getInnerQuery();
 	ASTSelectQuery & inner_select = static_cast<ASTSelectQuery &>(*inner_query_clone);