diff --git a/dbms/include/DB/DataTypes/DataTypeAggregateFunction.h b/dbms/include/DB/DataTypes/DataTypeAggregateFunction.h
index 0e7871a66bd..47232f85711 100644
--- a/dbms/include/DB/DataTypes/DataTypeAggregateFunction.h
+++ b/dbms/include/DB/DataTypes/DataTypeAggregateFunction.h
@@ -54,6 +54,11 @@ public:
 	void serializeTextQuoted(const IColumn & column, size_t row_num, WriteBuffer & ostr) const;
 	void deserializeTextQuoted(IColumn & column, ReadBuffer & istr) const;
 
+	void serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
+	void deserializeTextJSON(IColumn & column, ReadBuffer & istr) const override;
+	void serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
+	void deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const override;
+
 	void serializeText(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
 	void serializeTextXML(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
 
@@ -66,10 +71,6 @@ public:
 	}
 
 private:
-	void serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr, const NullValuesByteMap * null_map) const override;
-	void deserializeTextJSONImpl(IColumn & column, ReadBuffer & istr, NullValuesByteMap * null_map) const override;
-	void serializeTextCSVImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr, const NullValuesByteMap * null_map) const override;
-	void deserializeTextCSVImpl(IColumn & column, ReadBuffer & istr, const char delimiter, NullValuesByteMap * null_map) const override;
 };
 
 
diff --git a/dbms/include/DB/DataTypes/DataTypeArray.h b/dbms/include/DB/DataTypes/DataTypeArray.h
index e820ac03dba..b97a4446c37 100644
--- a/dbms/include/DB/DataTypes/DataTypeArray.h
+++ b/dbms/include/DB/DataTypes/DataTypeArray.h
@@ -62,6 +62,12 @@ public:
 
 	void serializeTextXML(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
 
+
+	void serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
+	void deserializeTextJSON(IColumn & column, ReadBuffer & istr) const override;
+	void serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
+	void deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const override;
+
 	/** Записать размеры. */
 	void serializeOffsets(const IColumn & column, WriteBuffer & ostr, size_t offset = 0, size_t limit = 0) const;
 
@@ -83,11 +89,6 @@ public:
 private:
 	void serializeTextInternal(const IColumn & column, size_t row_num, WriteBuffer & ostr) const;
 	void deserializeTextQuotedInternal(IColumn & column, ReadBuffer & istr) const;
-
-	void serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr, const NullValuesByteMap * null_map) const override;
-	void deserializeTextJSONImpl(IColumn & column, ReadBuffer & istr, NullValuesByteMap * null_map) const override;
-	void serializeTextCSVImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr, const NullValuesByteMap * null_map) const override;
-	void deserializeTextCSVImpl(IColumn & column, ReadBuffer & istr, const char delimiter, NullValuesByteMap * null_map) const override;
 };
 
 }
diff --git a/dbms/include/DB/DataTypes/DataTypeDate.h b/dbms/include/DB/DataTypes/DataTypeDate.h
index 836e6ca2ca8..e7c7e2ac30a 100644
--- a/dbms/include/DB/DataTypes/DataTypeDate.h
+++ b/dbms/include/DB/DataTypes/DataTypeDate.h
@@ -54,60 +54,34 @@ private:
 		static_cast<ColumnType &>(column).getData().push_back(x);	/// Важно делать это в конце - для exception safety.
 	}
 
-	void serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr, const NullValuesByteMap * null_map) const override
+	void serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override
 	{
-		if (isNullValue(null_map, row_num))
-			writeCString(NullSymbol::JSON::name, ostr);
-		else
-		{
-			writeChar('"', ostr);
-			writeDateText(DayNum_t(static_cast<const ColumnType &>(column).getData()[row_num]), ostr);
-			writeChar('"', ostr);
-		}
+		writeChar('"', ostr);
+		writeDateText(DayNum_t(static_cast<const ColumnType &>(column).getData()[row_num]), ostr);
+		writeChar('"', ostr);
 	}
 
-	void deserializeTextJSONImpl(IColumn & column, ReadBuffer & istr, NullValuesByteMap * null_map) const override
+	void deserializeTextJSON(IColumn & column, ReadBuffer & istr) const override
 	{
-		if (NullSymbol::Deserializer<NullSymbol::JSON>::execute(column, istr, null_map))
-		{
-			FieldType default_val = get<FieldType>(getDefault());
-			static_cast<ColumnType &>(column).getData().push_back(default_val);
-		}
-		else
-		{
-			DayNum_t x;
-			assertChar('"', istr);
-			readDateText(x, istr);
-			assertChar('"', istr);
-			static_cast<ColumnType &>(column).getData().push_back(x);
-		}
+		DayNum_t x;
+		assertChar('"', istr);
+		readDateText(x, istr);
+		assertChar('"', istr);
+		static_cast<ColumnType &>(column).getData().push_back(x);
 	}
 
-	void serializeTextCSVImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr, const NullValuesByteMap * null_map) const override
+	void serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override
 	{
-		if (isNullValue(null_map, row_num))
-			writeCString(NullSymbol::CSV::name, ostr);
-		else
-		{
-			writeChar('"', ostr);
-			writeDateText(DayNum_t(static_cast<const ColumnType &>(column).getData()[row_num]), ostr);
-			writeChar('"', ostr);
-		}
+		writeChar('"', ostr);
+		writeDateText(DayNum_t(static_cast<const ColumnType &>(column).getData()[row_num]), ostr);
+		writeChar('"', ostr);
 	}
 
-	void deserializeTextCSVImpl(IColumn & column, ReadBuffer & istr, const char delimiter, NullValuesByteMap * null_map) const override
+	void deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const override
 	{
-		if (NullSymbol::Deserializer<NullSymbol::CSV>::execute(column, istr, null_map))
-		{
-			FieldType default_val = get<FieldType>(getDefault());
-			static_cast<ColumnType &>(column).getData().push_back(default_val);
-		}
-		else
-		{
-			LocalDate value;
-			readCSV(value, istr);
-			static_cast<ColumnType &>(column).getData().push_back(value.getDayNum());
-		}
+		LocalDate value;
+		readCSV(value, istr);
+		static_cast<ColumnType &>(column).getData().push_back(value.getDayNum());
 	}
 };
 
diff --git a/dbms/include/DB/DataTypes/DataTypeDateTime.h b/dbms/include/DB/DataTypes/DataTypeDateTime.h
index 3af0321d649..b86cbe10f76 100644
--- a/dbms/include/DB/DataTypes/DataTypeDateTime.h
+++ b/dbms/include/DB/DataTypes/DataTypeDateTime.h
@@ -54,64 +54,34 @@ private:
 		static_cast<ColumnType &>(column).getData().push_back(x);	/// Важно делать это в конце - для exception safety.
 	}
 
-	void serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-		const NullValuesByteMap * null_map) const override
+	void serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override
 	{
-		if (isNullValue(null_map, row_num))
-			writeCString(NullSymbol::JSON::name, ostr);
-		else
-		{
-			writeChar('"', ostr);
-			serializeText(column, row_num, ostr);
-			writeChar('"', ostr);
-		}
+		writeChar('"', ostr);
+		serializeText(column, row_num, ostr);
+		writeChar('"', ostr);
 	}
 
-	void deserializeTextJSONImpl(IColumn & column, ReadBuffer & istr,
-		NullValuesByteMap * null_map) const override
+	void deserializeTextJSON(IColumn & column, ReadBuffer & istr) const override
 	{
-		if (NullSymbol::Deserializer<NullSymbol::JSON>::execute(column, istr, null_map))
-		{
-			FieldType default_val = get<FieldType>(getDefault());
-			static_cast<ColumnType &>(column).getData().push_back(default_val);
-		}
-		else
-		{
-			time_t x;
-			assertChar('"', istr);
-			readDateTimeText(x, istr);
-			assertChar('"', istr);
-			static_cast<ColumnType &>(column).getData().push_back(x);
-		}
+		time_t x;
+		assertChar('"', istr);
+		readDateTimeText(x, istr);
+		assertChar('"', istr);
+		static_cast<ColumnType &>(column).getData().push_back(x);
 	}
 
-	void serializeTextCSVImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-		const NullValuesByteMap * null_map) const override
+	void serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override
 	{
-		if (isNullValue(null_map, row_num))
-			writeCString(NullSymbol::CSV::name, ostr);
-		else
-		{
-			writeChar('"', ostr);
-			serializeText(column, row_num, ostr);
-			writeChar('"', ostr);
-		}
+		writeChar('"', ostr);
+		serializeText(column, row_num, ostr);
+		writeChar('"', ostr);
 	}
 
-	void deserializeTextCSVImpl(IColumn & column, ReadBuffer & istr, const char delimiter,
-		NullValuesByteMap * null_map) const override
+	void deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const override
 	{
-		if (NullSymbol::Deserializer<NullSymbol::CSV>::execute(column, istr, null_map))
-		{
-			FieldType default_val = get<FieldType>(getDefault());
-			static_cast<ColumnType &>(column).getData().push_back(default_val);
-		}
-		else
-		{
-			LocalDateTime value;
-			readCSV(value, istr);
-			static_cast<ColumnType &>(column).getData().push_back(static_cast<time_t>(value));
-		}
+		LocalDateTime value;
+		readCSV(value, istr);
+		static_cast<ColumnType &>(column).getData().push_back(static_cast<time_t>(value));
 	}
 };
 
diff --git a/dbms/include/DB/DataTypes/DataTypeEnum.h b/dbms/include/DB/DataTypes/DataTypeEnum.h
index 737fd837c89..a7a38510ae4 100644
--- a/dbms/include/DB/DataTypes/DataTypeEnum.h
+++ b/dbms/include/DB/DataTypes/DataTypeEnum.h
@@ -85,6 +85,11 @@ public:
 	void serializeTextQuoted(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
 	void deserializeTextQuoted(IColumn & column, ReadBuffer & istr) const override;
 
+	void serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
+	void deserializeTextJSON(IColumn & column, ReadBuffer & istr) const override;
+	void serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
+	void deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const override;
+
 	void serializeText(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
 	void serializeTextXML(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
 
@@ -94,13 +99,6 @@ public:
 	ColumnPtr createConstColumn(const size_t size, const Field & field) const override;
 
 	Field getDefault() const override;
-
-private:
-
-	void serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr, const NullValuesByteMap * null_map) const override;
-	void deserializeTextJSONImpl(IColumn & column, ReadBuffer & istr, NullValuesByteMap * null_map) const override;
-	void serializeTextCSVImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr, const NullValuesByteMap * null_map) const override;
-	void deserializeTextCSVImpl(IColumn & column, ReadBuffer & istr, const char delimiter, NullValuesByteMap * null_map) const override;
 };
 
 
diff --git a/dbms/include/DB/DataTypes/DataTypeFixedString.h b/dbms/include/DB/DataTypes/DataTypeFixedString.h
index c3af894113d..4b1388ef10c 100644
--- a/dbms/include/DB/DataTypes/DataTypeFixedString.h
+++ b/dbms/include/DB/DataTypes/DataTypeFixedString.h
@@ -49,6 +49,11 @@ public:
 	void serializeTextQuoted(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
 	void deserializeTextQuoted(IColumn & column, ReadBuffer & istr) const override;
 
+	void serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
+	void deserializeTextJSON(IColumn & column, ReadBuffer & istr) const override;
+	void serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
+	void deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const override;
+
 	void serializeText(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
 	void serializeTextXML(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
 
@@ -59,13 +64,6 @@ public:
 	{
 		return String();
 	}
-
-private:
-
-	void serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr, const NullValuesByteMap * null_map) const override;
-	void deserializeTextJSONImpl(IColumn & column, ReadBuffer & istr, NullValuesByteMap * null_map) const override;
-	void serializeTextCSVImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr, const NullValuesByteMap * null_map) const override;
-	void deserializeTextCSVImpl(IColumn & column, ReadBuffer & istr, const char delimiter, NullValuesByteMap * null_map) const override;
 };
 
 }
diff --git a/dbms/include/DB/DataTypes/DataTypeNull.h b/dbms/include/DB/DataTypes/DataTypeNull.h
index 987272a63aa..a16181c0a25 100644
--- a/dbms/include/DB/DataTypes/DataTypeNull.h
+++ b/dbms/include/DB/DataTypes/DataTypeNull.h
@@ -22,17 +22,15 @@ public:
 	void deserializeTextEscaped(IColumn & column, ReadBuffer & istr) const override;
 	void serializeTextQuoted(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
 	void deserializeTextQuoted(IColumn & column, ReadBuffer & istr) const override;
+	void serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
+	void deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const override;
+	void serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
+	void deserializeTextJSON(IColumn & column, ReadBuffer & istr) const override;
 	void serializeText(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
 	ColumnPtr createColumn() const override;
 	ColumnPtr createConstColumn(size_t size, const Field & field) const override;
 	Field getDefault() const override;
 	size_t getSizeOfField() const override;
-
-private:
-	void serializeTextCSVImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr, const NullValuesByteMap * null_map) const override;
-	void deserializeTextCSVImpl(IColumn & column, ReadBuffer & istr, const char delimiter, NullValuesByteMap * null_map) const override;
-	void serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr, const NullValuesByteMap * null_map) const override;
-	void deserializeTextJSONImpl(IColumn & column, ReadBuffer & istr, NullValuesByteMap * null_map) const override;
 };
 
 }
diff --git a/dbms/include/DB/DataTypes/DataTypeNullable.h b/dbms/include/DB/DataTypes/DataTypeNullable.h
index ecdd903e492..c503454f315 100644
--- a/dbms/include/DB/DataTypes/DataTypeNullable.h
+++ b/dbms/include/DB/DataTypes/DataTypeNullable.h
@@ -24,6 +24,10 @@ public:
 	void deserializeTextEscaped(IColumn & column, ReadBuffer & istr) const override;
 	void serializeTextQuoted(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
 	void deserializeTextQuoted(IColumn & column, ReadBuffer & istr) const override;
+	void serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
+	void deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const override;
+	void serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
+	void deserializeTextJSON(IColumn & column, ReadBuffer & istr) const override;
 	void serializeText(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
 	void serializeTextXML(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
 	ColumnPtr createColumn() const override;
@@ -33,12 +37,6 @@ public:
 	DataTypePtr & getNestedType();
 	const DataTypePtr & getNestedType() const;
 
-private:
-	void serializeTextCSVImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr, const NullValuesByteMap * null_map) const override;
-	void deserializeTextCSVImpl(IColumn & column, ReadBuffer & istr, const char delimiter, NullValuesByteMap * null_map) const override;
-	void serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr, const NullValuesByteMap * null_map) const override;
-	void deserializeTextJSONImpl(IColumn & column, ReadBuffer & istr, NullValuesByteMap * null_map) const override;
-
 private:
 	DataTypePtr nested_data_type;
 };
diff --git a/dbms/include/DB/DataTypes/DataTypeString.h b/dbms/include/DB/DataTypes/DataTypeString.h
index 0e781effbb8..34bbb47bf12 100644
--- a/dbms/include/DB/DataTypes/DataTypeString.h
+++ b/dbms/include/DB/DataTypes/DataTypeString.h
@@ -36,6 +36,11 @@ public:
 	void serializeTextQuoted(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
 	void deserializeTextQuoted(IColumn & column, ReadBuffer & istr) const override;
 
+	void serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
+	void deserializeTextJSON(IColumn & column, ReadBuffer & istr) const override;
+	void serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
+	void deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const override;
+
 	void serializeText(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
 	void serializeTextXML(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
 
@@ -46,13 +51,6 @@ public:
 	{
 		return String("");
 	}
-
-private:
-
-	void serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr, const NullValuesByteMap * null_map) const override;
-	void deserializeTextJSONImpl(IColumn & column, ReadBuffer & istr, NullValuesByteMap * null_map) const override;
-	void serializeTextCSVImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr, const NullValuesByteMap * null_map) const override;
-	void deserializeTextCSVImpl(IColumn & column, ReadBuffer & istr, const char delimiter, NullValuesByteMap * null_map) const override;
 };
 
 }
diff --git a/dbms/include/DB/DataTypes/DataTypeTuple.h b/dbms/include/DB/DataTypes/DataTypeTuple.h
index ced1eac75df..269675dde27 100644
--- a/dbms/include/DB/DataTypes/DataTypeTuple.h
+++ b/dbms/include/DB/DataTypes/DataTypeTuple.h
@@ -39,6 +39,13 @@ public:
 	void serializeTextQuoted(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
 	void deserializeTextQuoted(IColumn & column, ReadBuffer & istr) const override;
 
+	void serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
+	void deserializeTextJSON(IColumn & column, ReadBuffer & istr) const override;
+
+	/// Кортежи в формате CSV будем сериализовать, как отдельные столбцы (то есть, теряя их вложенность в кортеж).
+	void serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
+	void deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const override;
+
 	void serializeText(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
 	void serializeTextXML(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
 
@@ -50,12 +57,6 @@ public:
 
 private:
 	void deserializeText(IColumn & column, ReadBuffer & istr) const;
-	void serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr, const NullValuesByteMap * null_map) const override;
-	void deserializeTextJSONImpl(IColumn & column, ReadBuffer & istr, NullValuesByteMap * null_map) const override;
-
-	/// Кортежи в формате CSV будем сериализовать, как отдельные столбцы (то есть, теряя их вложенность в кортеж).
-	void serializeTextCSVImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr, const NullValuesByteMap * null_map) const override;
-	void deserializeTextCSVImpl(IColumn & column, ReadBuffer & istr, const char delimiter, NullValuesByteMap * null_map) const override;
 };
 
 }
diff --git a/dbms/include/DB/DataTypes/IDataType.h b/dbms/include/DB/DataTypes/IDataType.h
index ebe058ec928..3c63a5e8b69 100644
--- a/dbms/include/DB/DataTypes/IDataType.h
+++ b/dbms/include/DB/DataTypes/IDataType.h
@@ -86,19 +86,11 @@ public:
 
 	/** Text serialization for the CSV format.
 	  */
-	inline void serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-		const PaddedPODArray<UInt8> * null_map = nullptr) const
-	{
-		serializeTextCSVImpl(column, row_num, ostr, null_map);
-	}
+	virtual void serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr) const = 0;
 
 	/** delimiter - the delimiter we expect when reading a value that is not double-quoted.
 	  */
-	inline void deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter,
-		PaddedPODArray<UInt8> * null_map = nullptr) const
-	{
-		deserializeTextCSVImpl(column, istr, delimiter, null_map);
-	}
+	virtual void deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const = 0;
 
 	/** Text serialization for displaying on a terminal or saving into a text file, and the like.
 	  * Without escaping or quoting.
@@ -107,17 +99,8 @@ public:
 
 	/** Text serialization as a literal for using with the JSON format.
 	  */
-	inline void serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-		const PaddedPODArray<UInt8> * null_map = nullptr) const
-	{
-		serializeTextJSONImpl(column, row_num, ostr, null_map);
-	}
-
-	inline void deserializeTextJSON(IColumn & column, ReadBuffer & istr,
-		PaddedPODArray<UInt8> * null_map = nullptr) const
-	{
-		deserializeTextJSONImpl(column, istr, null_map);
-	}
+	virtual void serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const = 0;
+	virtual void deserializeTextJSON(IColumn & column, ReadBuffer & istr) const = 0;
 
 	/** Text serialization for putting into the XML format.
 	  */
@@ -151,11 +134,6 @@ protected:
 	{
 		return (null_map != nullptr) && ((*null_map)[row_num] == 1);
 	}
-
-	virtual void serializeTextCSVImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr, const NullValuesByteMap * null_map) const = 0;
-	virtual void deserializeTextCSVImpl(IColumn & column, ReadBuffer & istr, const char delimiter, NullValuesByteMap * null_map) const = 0;
-	virtual void serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr, const NullValuesByteMap * null_map) const = 0;
-	virtual void deserializeTextJSONImpl(IColumn & column, ReadBuffer & istr, NullValuesByteMap * null_map) const = 0;
 };
 
 
diff --git a/dbms/include/DB/DataTypes/IDataTypeDummy.h b/dbms/include/DB/DataTypes/IDataTypeDummy.h
index 37ad21af0b8..2f7c0b1db54 100644
--- a/dbms/include/DB/DataTypes/IDataTypeDummy.h
+++ b/dbms/include/DB/DataTypes/IDataTypeDummy.h
@@ -40,6 +40,11 @@ public:
 		throwNoSerialization();
 	}
 
+	void deserializeBinary(IColumn & column, ReadBuffer & istr, size_t limit, double avg_value_size_hint) const override
+	{
+		throwNoSerialization();
+	}
+
 	void serializeTextEscaped(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override
 	{
 		throwNoSerialization();
@@ -60,7 +65,22 @@ public:
 		throwNoSerialization();
 	}
 
-	void deserializeBinary(IColumn & column, ReadBuffer & istr, size_t limit, double avg_value_size_hint) const override
+	void serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override
+	{
+		throwNoSerialization();
+	}
+
+	void deserializeTextJSON(IColumn & column, ReadBuffer & istr) const override
+	{
+		throwNoSerialization();
+	}
+
+	void serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override
+	{
+		throwNoSerialization();
+	}
+
+	void deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const override
 	{
 		throwNoSerialization();
 	}
@@ -85,31 +105,6 @@ public:
 		throw Exception("Method getDefault() is not implemented for data type " + getName(), ErrorCodes::NOT_IMPLEMENTED);
 	}
 
-protected:
-	void serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-		const NullValuesByteMap * null_map) const override
-	{
-		throwNoSerialization();
-	}
-
-	void deserializeTextJSONImpl(IColumn & column, ReadBuffer & istr,
-		NullValuesByteMap * null_map) const override
-	{
-		throwNoSerialization();
-	}
-
-	void serializeTextCSVImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-		const NullValuesByteMap * null_map) const override
-	{
-		throwNoSerialization();
-	}
-
-	void deserializeTextCSVImpl(IColumn & column, ReadBuffer & istr, const char delimiter,
-		NullValuesByteMap * null_map) const override
-	{
-		throwNoSerialization();
-	}
-
 private:
 	void throwNoSerialization() const
 	{
diff --git a/dbms/include/DB/DataTypes/IDataTypeNumber.h b/dbms/include/DB/DataTypes/IDataTypeNumber.h
index 9b1fab08e6a..b5b712223e6 100644
--- a/dbms/include/DB/DataTypes/IDataTypeNumber.h
+++ b/dbms/include/DB/DataTypes/IDataTypeNumber.h
@@ -66,11 +66,9 @@ protected:
 		deserializeText<NullSymbol::Quoted>(column, istr);
 	}
 
-	inline void serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-		const PaddedPODArray<UInt8> * null_map) const override;
+	inline void serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override;
 
-	void deserializeTextJSONImpl(IColumn & column, ReadBuffer & istr,
-		PaddedPODArray<UInt8> * null_map) const override
+	void deserializeTextJSON(IColumn & column, ReadBuffer & istr) const override
 	{
 		bool has_quote = false;
 		if (!istr.eof() && *istr.position() == '"')		/// Понимаем число как в кавычках, так и без.
@@ -88,9 +86,6 @@ protected:
 			assertString(NullSymbol::JSON::suffix, istr);
 
 			x = valueForJSONNull();
-
-			if (null_map != nullptr)
-				null_map->push_back(1);
 		}
 		else
 		{
@@ -103,29 +98,16 @@ protected:
 		static_cast<ColumnType &>(column).getData().push_back(x);
 	}
 
-	void serializeTextCSVImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-		const PaddedPODArray<UInt8> * null_map) const override
+	void serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override
 	{
-		if (isNullValue(null_map, row_num))
-			writeCString(NullSymbol::CSV::name, ostr);
-		else
-			writeText(static_cast<const ColumnType &>(column).getData()[row_num], ostr);
+		writeText(static_cast<const ColumnType &>(column).getData()[row_num], ostr);
 	}
 
-	void deserializeTextCSVImpl(IColumn & column, ReadBuffer & istr, const char delimiter,
-		PaddedPODArray<UInt8> * null_map) const override
+	void deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const override
 	{
-		if (NullSymbol::Deserializer<NullSymbol::CSV>::execute(column, istr, null_map))
-		{
-			FieldType default_val = get<FieldType>(getDefault());
-			static_cast<ColumnType &>(column).getData().push_back(default_val);
-		}
-		else
-		{
-			FieldType x;
-			readCSV(x, istr);
-			static_cast<ColumnType &>(column).getData().push_back(x);
-		}
+		FieldType x;
+		readCSV(x, istr);
+		static_cast<ColumnType &>(column).getData().push_back(x);
 	}
 };
 
@@ -143,83 +125,53 @@ public:
 	void deserializeTextEscaped(IColumn & column, ReadBuffer & istr) const override {}
 	void serializeTextQuoted(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override {}
 	void deserializeTextQuoted(IColumn & column, ReadBuffer & istr) const override {}
+	void serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override {}
+	void deserializeTextJSON(IColumn & column, ReadBuffer & istr) const override {}
+	void serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override {}
+	void deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const override {}
 	void serializeText(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override {}
-
-protected:
-	void serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr, const PaddedPODArray<UInt8> * null_map) const override {}
-	void deserializeTextJSONImpl(IColumn & column, ReadBuffer & istr, PaddedPODArray<UInt8> * null_map) const override {}
-	void serializeTextCSVImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr, const PaddedPODArray<UInt8> * null_map) const override {}
-	void deserializeTextCSVImpl(IColumn & column, ReadBuffer & istr, const char delimiter, PaddedPODArray<UInt8> * null_map) const override {}
 };
 
 template <typename FType>
-inline void IDataTypeNumber<FType>::serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-	const PaddedPODArray<UInt8> * null_map) const
+inline void IDataTypeNumber<FType>::serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
 {
-	if (isNullValue(null_map, row_num))
-		writeCString(NullSymbol::JSON::name, ostr);
-	else
-		writeText(static_cast<const ColumnType &>(column).getData()[row_num], ostr);
+	writeText(static_cast<const ColumnType &>(column).getData()[row_num], ostr);
 }
 
 template <>
-inline void IDataTypeNumber<Int64>::serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-	const PaddedPODArray<UInt8> * null_map) const
+inline void IDataTypeNumber<Int64>::serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
 {
-	if (isNullValue(null_map, row_num))
-		writeCString(NullSymbol::JSON::name, ostr);
-	else
-	{
-		writeChar('"', ostr);
-		writeText(static_cast<const ColumnType &>(column).getData()[row_num], ostr);
-		writeChar('"', ostr);
-	}
+	writeChar('"', ostr);
+	writeText(static_cast<const ColumnType &>(column).getData()[row_num], ostr);
+	writeChar('"', ostr);
 }
 
 template <>
-inline void IDataTypeNumber<UInt64>::serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-	const PaddedPODArray<UInt8> * null_map) const
+inline void IDataTypeNumber<UInt64>::serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
 {
-	if (isNullValue(null_map, row_num))
-		writeCString(NullSymbol::JSON::name, ostr);
-	else
-	{
-		writeChar('"', ostr);
-		writeText(static_cast<const ColumnType &>(column).getData()[row_num], ostr);
-		writeChar('"', ostr);
-	}
+	writeChar('"', ostr);
+	writeText(static_cast<const ColumnType &>(column).getData()[row_num], ostr);
+	writeChar('"', ostr);
 }
 
 template <>
-inline void IDataTypeNumber<Float32>::serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-	const PaddedPODArray<UInt8> * null_map) const
+inline void IDataTypeNumber<Float32>::serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
 {
-	if (isNullValue(null_map, row_num))
-		writeCString(NullSymbol::JSON::name, ostr);
+	auto x = static_cast<const ColumnType &>(column).getData()[row_num];
+	if (likely(std::isfinite(x)))
+		writeText(x, ostr);
 	else
-	{
-		auto x = static_cast<const ColumnType &>(column).getData()[row_num];
-		if (likely(std::isfinite(x)))
-			writeText(x, ostr);
-		else
-			writeCString(NullSymbol::JSON::name, ostr);
-	}
+		writeCString(NullSymbol::JSON::name, ostr);
 }
 
 template <>
-inline void IDataTypeNumber<Float64>::serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-	const PaddedPODArray<UInt8> * null_map) const
+inline void IDataTypeNumber<Float64>::serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
 {
-	if (isNullValue(null_map, row_num))
-		writeCString(NullSymbol::JSON::name, ostr);
+	auto x = static_cast<const ColumnType &>(column).getData()[row_num];
+	if (likely(std::isfinite(x)))
+		writeText(x, ostr);
 	else
-	{
-		auto x = static_cast<const ColumnType &>(column).getData()[row_num];
-		if (likely(std::isfinite(x)))
-			writeText(x, ostr);
-		else
-			writeCString(NullSymbol::JSON::name, ostr);
-	}
+		writeCString(NullSymbol::JSON::name, ostr);
 }
 
 template <typename FType>
diff --git a/dbms/src/DataTypes/DataTypeAggregateFunction.cpp b/dbms/src/DataTypes/DataTypeAggregateFunction.cpp
index 671d1a8e8ac..d5b11628b91 100644
--- a/dbms/src/DataTypes/DataTypeAggregateFunction.cpp
+++ b/dbms/src/DataTypes/DataTypeAggregateFunction.cpp
@@ -188,14 +188,12 @@ void DataTypeAggregateFunction::deserializeTextQuoted(IColumn & column, ReadBuff
 	deserializeFromString(function, column, s);
 }
 
-void DataTypeAggregateFunction::serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-	const NullValuesByteMap * null_map) const
+void DataTypeAggregateFunction::serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
 {
 	writeJSONString(serializeToString(function, column, row_num), ostr);
 }
 
-void DataTypeAggregateFunction::deserializeTextJSONImpl(IColumn & column, ReadBuffer & istr,
-	NullValuesByteMap * null_map) const
+void DataTypeAggregateFunction::deserializeTextJSON(IColumn & column, ReadBuffer & istr) const
 {
 	String s;
 	readJSONString(s, istr);
@@ -207,14 +205,12 @@ void DataTypeAggregateFunction::serializeTextXML(const IColumn & column, size_t
 	writeXMLString(serializeToString(function, column, row_num), ostr);
 }
 
-void DataTypeAggregateFunction::serializeTextCSVImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-	const NullValuesByteMap * null_map) const
+void DataTypeAggregateFunction::serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
 {
 	writeCSV(serializeToString(function, column, row_num), ostr);
 }
 
-void DataTypeAggregateFunction::deserializeTextCSVImpl(IColumn & column, ReadBuffer & istr, const char delimiter,
-	NullValuesByteMap * null_map) const
+void DataTypeAggregateFunction::deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const
 {
 	String s;
 	readCSV(s, istr, delimiter);
diff --git a/dbms/src/DataTypes/DataTypeArray.cpp b/dbms/src/DataTypes/DataTypeArray.cpp
index c74e87175d8..0870533331f 100644
--- a/dbms/src/DataTypes/DataTypeArray.cpp
+++ b/dbms/src/DataTypes/DataTypeArray.cpp
@@ -262,13 +262,6 @@ void deserializeTextInternal(IColumn & column, ReadBuffer & istr, Reader && read
 	offsets.push_back((offsets.empty() ? 0 : offsets.back()) + size);
 }
 
-void insertEmptyArray(IColumn & column)
-{
-	ColumnArray & column_array = static_cast<ColumnArray &>(column);
-	ColumnArray::Offsets_t & offsets = column_array.getOffsets();
-	offsets.push_back((offsets.empty() ? 0 : offsets.back()));
-}
-
 }
 
 void DataTypeArray::deserializeTextQuotedInternal(IColumn & column, ReadBuffer & istr) const
@@ -306,40 +299,30 @@ void DataTypeArray::deserializeTextQuoted(IColumn & column, ReadBuffer & istr) c
 }
 
 
-void DataTypeArray::serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-	const NullValuesByteMap * null_map) const
+void DataTypeArray::serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
 {
-	if (isNullValue(null_map, row_num))
-		writeCString(NullSymbol::JSON::name, ostr);
-	else
+	const ColumnArray & column_array = static_cast<const ColumnArray &>(column);
+	const ColumnArray::Offsets_t & offsets = column_array.getOffsets();
+
+	size_t offset = row_num == 0 ? 0 : offsets[row_num - 1];
+	size_t next_offset = offsets[row_num];
+
+	const IColumn & nested_column = column_array.getData();
+
+	writeChar('[', ostr);
+	for (size_t i = offset; i < next_offset; ++i)
 	{
-		const ColumnArray & column_array = static_cast<const ColumnArray &>(column);
-		const ColumnArray::Offsets_t & offsets = column_array.getOffsets();
-
-		size_t offset = row_num == 0 ? 0 : offsets[row_num - 1];
-		size_t next_offset = offsets[row_num];
-
-		const IColumn & nested_column = column_array.getData();
-
-		writeChar('[', ostr);
-		for (size_t i = offset; i < next_offset; ++i)
-		{
-			if (i != offset)
-				writeChar(',', ostr);
-			nested->serializeTextJSON(nested_column, i, ostr, null_map);
-		}
-		writeChar(']', ostr);
+		if (i != offset)
+			writeChar(',', ostr);
+		nested->serializeTextJSON(nested_column, i, ostr);
 	}
+	writeChar(']', ostr);
 }
 
 
-void DataTypeArray::deserializeTextJSONImpl(IColumn & column, ReadBuffer & istr,
-	NullValuesByteMap * null_map) const
+void DataTypeArray::deserializeTextJSON(IColumn & column, ReadBuffer & istr) const
 {
-	if (NullSymbol::Deserializer<NullSymbol::JSON>::execute(column, istr, null_map))
-		insertEmptyArray(column);
-	else
-		deserializeTextInternal(column, istr, [&](IColumn & nested_column) { nested->deserializeTextJSON(nested_column, istr); });
+	deserializeTextInternal(column, istr, [&](IColumn & nested_column) { nested->deserializeTextJSON(nested_column, istr); });
 }
 
 
@@ -364,36 +347,24 @@ void DataTypeArray::serializeTextXML(const IColumn & column, size_t row_num, Wri
 }
 
 
-void DataTypeArray::serializeTextCSVImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-	const NullValuesByteMap * null_map) const
+void DataTypeArray::serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
 {
-	if (isNullValue(null_map, row_num))
-		writeCString(NullSymbol::Quoted::name, ostr);
-	else
+	/// Хорошего способа сериализовать массив в CSV нет. Поэтому сериализуем его в строку, а затем полученную строку запишем в CSV.
+	String s;
 	{
-		/// Хорошего способа сериализовать массив в CSV нет. Поэтому сериализуем его в строку, а затем полученную строку запишем в CSV.
-		String s;
-		{
-			WriteBufferFromString wb(s);
-			serializeTextInternal(column, row_num, wb);
-		}
-		writeCSV(s, ostr);
+		WriteBufferFromString wb(s);
+		serializeTextInternal(column, row_num, wb);
 	}
+	writeCSV(s, ostr);
 }
 
 
-void DataTypeArray::deserializeTextCSVImpl(IColumn & column, ReadBuffer & istr, const char delimiter,
-	NullValuesByteMap * null_map) const
+void DataTypeArray::deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const
 {
-	if (NullSymbol::Deserializer<NullSymbol::Quoted>::execute(column, istr, null_map))
-		insertEmptyArray(column);
-	else
-	{
-		String s;
-		readCSV(s, istr, delimiter);
-		ReadBufferFromString rb(s);
-		deserializeTextQuotedInternal(column, rb);
-	}
+	String s;
+	readCSV(s, istr, delimiter);
+	ReadBufferFromString rb(s);
+	deserializeTextQuotedInternal(column, rb);
 }
 
 
diff --git a/dbms/src/DataTypes/DataTypeEnum.cpp b/dbms/src/DataTypes/DataTypeEnum.cpp
index 50098284ff4..57da928119d 100644
--- a/dbms/src/DataTypes/DataTypeEnum.cpp
+++ b/dbms/src/DataTypes/DataTypeEnum.cpp
@@ -171,13 +171,9 @@ void DataTypeEnum<Type>::deserializeTextQuoted(IColumn & column, ReadBuffer & is
 }
 
 template <typename Type>
-void DataTypeEnum<Type>::serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-	const NullValuesByteMap * null_map) const
+void DataTypeEnum<Type>::serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
 {
-	if (isNullValue(null_map, row_num))
-		writeCString(NullSymbol::JSON::name, ostr);
-	else
-		writeJSONString(getNameForValue(static_cast<const ColumnType &>(column).getData()[row_num]), ostr);
+	writeJSONString(getNameForValue(static_cast<const ColumnType &>(column).getData()[row_num]), ostr);
 }
 
 template <typename Type>
@@ -187,47 +183,25 @@ void DataTypeEnum<Type>::serializeTextXML(const IColumn & column, size_t row_num
 }
 
 template <typename Type>
-void DataTypeEnum<Type>::deserializeTextJSONImpl(IColumn & column, ReadBuffer & istr,
-	NullValuesByteMap * null_map) const
+void DataTypeEnum<Type>::deserializeTextJSON(IColumn & column, ReadBuffer & istr) const
 {
-	if (NullSymbol::Deserializer<NullSymbol::JSON>::execute(column, istr, null_map))
-	{
-		FieldType default_val = get<FieldType>(getDefault());
-		static_cast<ColumnType &>(column).getData().push_back(default_val);
-	}
-	else
-	{
-		std::string name;
-		readJSONString(name, istr);
-		static_cast<ColumnType &>(column).getData().push_back(getValue(StringRef(name)));
-	}
+	std::string name;
+	readJSONString(name, istr);
+	static_cast<ColumnType &>(column).getData().push_back(getValue(StringRef(name)));
 }
 
 template <typename Type>
-void DataTypeEnum<Type>::serializeTextCSVImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-	const NullValuesByteMap * null_map) const
+void DataTypeEnum<Type>::serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
 {
-	if (isNullValue(null_map, row_num))
-		writeCString(NullSymbol::CSV::name, ostr);
-	else
-		writeCSVString(getNameForValue(static_cast<const ColumnType &>(column).getData()[row_num]), ostr);
+	writeCSVString(getNameForValue(static_cast<const ColumnType &>(column).getData()[row_num]), ostr);
 }
 
 template <typename Type>
-void DataTypeEnum<Type>::deserializeTextCSVImpl(IColumn & column, ReadBuffer & istr, const char delimiter,
-	NullValuesByteMap * null_map) const
+void DataTypeEnum<Type>::deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const
 {
-	if (NullSymbol::Deserializer<NullSymbol::CSV>::execute(column, istr, null_map))
-	{
-		FieldType default_val = get<FieldType>(getDefault());
-		static_cast<ColumnType &>(column).getData().push_back(default_val);
-	}
-	else
-	{
-		std::string name;
-		readCSVString(name, istr, delimiter);
-		static_cast<ColumnType &>(column).getData().push_back(getValue(StringRef(name)));
-	}
+	std::string name;
+	readCSVString(name, istr, delimiter);
+	static_cast<ColumnType &>(column).getData().push_back(getValue(StringRef(name)));
 }
 
 template <typename Type>
diff --git a/dbms/src/DataTypes/DataTypeFixedString.cpp b/dbms/src/DataTypes/DataTypeFixedString.cpp
index 1ac9c3c7d12..b394cb108a1 100644
--- a/dbms/src/DataTypes/DataTypeFixedString.cpp
+++ b/dbms/src/DataTypes/DataTypeFixedString.cpp
@@ -141,13 +141,6 @@ static inline void read(const DataTypeFixedString & self, IColumn & column, Read
 	}
 }
 
-void insertEmptyString(const DataTypeFixedString & self, IColumn & column)
-{
-	ColumnFixedString::Chars_t & data = typeid_cast<ColumnFixedString &>(column).getChars();
-	size_t prev_size = data.size();
-	data.resize_fill(prev_size + self.getN());
-}
-
 }
 
 void DataTypeFixedString::deserializeTextEscaped(IColumn & column, ReadBuffer & istr) const
@@ -169,26 +162,16 @@ void DataTypeFixedString::deserializeTextQuoted(IColumn & column, ReadBuffer & i
 }
 
 
-void DataTypeFixedString::serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-	const NullValuesByteMap * null_map) const
+void DataTypeFixedString::serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
 {
-	if (isNullValue(null_map, row_num))
-		writeCString(NullSymbol::JSON::name, ostr);
-	else
-	{
-		const char * pos = reinterpret_cast<const char *>(&static_cast<const ColumnFixedString &>(column).getChars()[n * row_num]);
-		writeJSONString(pos, pos + n, ostr);
-	}
+	const char * pos = reinterpret_cast<const char *>(&static_cast<const ColumnFixedString &>(column).getChars()[n * row_num]);
+	writeJSONString(pos, pos + n, ostr);
 }
 
 
-void DataTypeFixedString::deserializeTextJSONImpl(IColumn & column, ReadBuffer & istr,
-	NullValuesByteMap * null_map) const
+void DataTypeFixedString::deserializeTextJSON(IColumn & column, ReadBuffer & istr) const
 {
-	if (NullSymbol::Deserializer<NullSymbol::JSON>::execute(column, istr, null_map))
-		insertEmptyString(*this, column);
-	else
-		read(*this, column, [&istr](ColumnFixedString::Chars_t & data) { readJSONStringInto(data, istr); });
+	read(*this, column, [&istr](ColumnFixedString::Chars_t & data) { readJSONStringInto(data, istr); });
 }
 
 
@@ -199,26 +182,16 @@ void DataTypeFixedString::serializeTextXML(const IColumn & column, size_t row_nu
 }
 
 
-void DataTypeFixedString::serializeTextCSVImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-	const NullValuesByteMap * null_map) const
+void DataTypeFixedString::serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
 {
-	if (isNullValue(null_map, row_num))
-		writeCString(NullSymbol::CSV::name, ostr);
-	else
-	{
-		const char * pos = reinterpret_cast<const char *>(&static_cast<const ColumnFixedString &>(column).getChars()[n * row_num]);
-		writeCSVString(pos, pos + n, ostr);
-	}
+	const char * pos = reinterpret_cast<const char *>(&static_cast<const ColumnFixedString &>(column).getChars()[n * row_num]);
+	writeCSVString(pos, pos + n, ostr);
 }
 
 
-void DataTypeFixedString::deserializeTextCSVImpl(IColumn & column, ReadBuffer & istr, const char delimiter,
-	NullValuesByteMap * null_map) const
+void DataTypeFixedString::deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const
 {
-	if (NullSymbol::Deserializer<NullSymbol::CSV>::execute(column, istr, null_map))
-		insertEmptyString(*this, column);
-	else
-		read(*this, column, [&istr](ColumnFixedString::Chars_t & data) { readCSVStringInto(data, istr); });
+	read(*this, column, [&istr](ColumnFixedString::Chars_t & data) { readCSVStringInto(data, istr); });
 }
 
 
diff --git a/dbms/src/DataTypes/DataTypeNull.cpp b/dbms/src/DataTypes/DataTypeNull.cpp
index 0ac288253b5..d789be1872a 100644
--- a/dbms/src/DataTypes/DataTypeNull.cpp
+++ b/dbms/src/DataTypes/DataTypeNull.cpp
@@ -121,14 +121,12 @@ void DataTypeNull::deserializeTextQuoted(IColumn & column, ReadBuffer & istr) co
 	assertString(NullSymbol::Quoted::name, istr);
 }
 
-void DataTypeNull::serializeTextCSVImpl(const IColumn & column, size_t row_num,
-	WriteBuffer & ostr, const NullValuesByteMap * null_map) const
+void DataTypeNull::serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
 {
 	writeCString(NullSymbol::CSV::name, ostr);
 }
 
-void DataTypeNull::deserializeTextCSVImpl(IColumn & column, ReadBuffer & istr,
-	const char delimiter, NullValuesByteMap * null_map) const
+void DataTypeNull::deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const
 {
 	assertString(NullSymbol::CSV::name, istr);
 }
@@ -138,14 +136,12 @@ void DataTypeNull::serializeText(const IColumn & column, size_t row_num, WriteBu
 	writeCString(NullSymbol::Plain::name, ostr);
 }
 
-void DataTypeNull::serializeTextJSONImpl(const IColumn & column, size_t row_num,
-	WriteBuffer & ostr, const NullValuesByteMap * null_map) const
+void DataTypeNull::serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
 {
 	writeCString(NullSymbol::JSON::name, ostr);
 }
 
-void DataTypeNull::deserializeTextJSONImpl(IColumn & column, ReadBuffer & istr,
-	NullValuesByteMap * null_map) const
+void DataTypeNull::deserializeTextJSON(IColumn & column, ReadBuffer & istr) const
 {
 	assertString(NullSymbol::JSON::name, istr);
 }
diff --git a/dbms/src/DataTypes/DataTypeNullable.cpp b/dbms/src/DataTypes/DataTypeNullable.cpp
index a7d9d260a56..e118c68d715 100644
--- a/dbms/src/DataTypes/DataTypeNullable.cpp
+++ b/dbms/src/DataTypes/DataTypeNullable.cpp
@@ -142,26 +142,34 @@ void DataTypeNullable::deserializeTextQuoted(IColumn & column, ReadBuffer & istr
 		nested_data_type.get()->deserializeTextQuoted(*(col->getNestedColumn().get()), istr);
 }
 
-void DataTypeNullable::serializeTextCSVImpl(const IColumn & column, size_t row_num,
-	WriteBuffer & ostr, const NullValuesByteMap * null_map) const
+void DataTypeNullable::serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
 {
 	const ColumnNullable * col = typeid_cast<const ColumnNullable *>(&column);
 	if (col == nullptr)
 		throw Exception{"Discrepancy between data type and column type", ErrorCodes::LOGICAL_ERROR};
 
 	const ColumnUInt8 & content = static_cast<const ColumnUInt8 &>(*(col->getNullValuesByteMap().get()));
-	nested_data_type.get()->serializeTextCSV(*(col->getNestedColumn().get()), row_num, ostr, &content.getData());
+	const auto & null_map = content.getData();
+
+	if (isNullValue(&null_map, row_num))
+		writeCString(NullSymbol::Quoted::name, ostr);
+	else
+		nested_data_type.get()->serializeTextCSV(*(col->getNestedColumn().get()), row_num, ostr);
 }
 
-void DataTypeNullable::deserializeTextCSVImpl(IColumn & column, ReadBuffer & istr,
-	const char delimiter, NullValuesByteMap * null_map) const
+void DataTypeNullable::deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const
 {
 	ColumnNullable * col = typeid_cast<ColumnNullable *>(&column);
 	if (col == nullptr)
 		throw Exception{"Discrepancy between data type and column type", ErrorCodes::LOGICAL_ERROR};
 
 	ColumnUInt8 & content = static_cast<ColumnUInt8 &>(*(col->getNullValuesByteMap().get()));
-	nested_data_type.get()->deserializeTextCSV(*(col->getNestedColumn().get()), istr, delimiter, &content.getData());
+	auto & null_map = content.getData();
+
+	if (NullSymbol::Deserializer<NullSymbol::Quoted>::execute(column, istr, &null_map))
+		col->insertDefault();
+	else
+		nested_data_type.get()->deserializeTextCSV(*(col->getNestedColumn().get()), istr, delimiter);
 }
 
 void DataTypeNullable::serializeText(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
@@ -179,26 +187,34 @@ void DataTypeNullable::serializeText(const IColumn & column, size_t row_num, Wri
 		nested_data_type.get()->serializeText(*(col->getNestedColumn().get()), row_num, ostr);
 }
 
-void DataTypeNullable::serializeTextJSONImpl(const IColumn & column, size_t row_num,
-	WriteBuffer & ostr, const NullValuesByteMap * null_map) const
+void DataTypeNullable::serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
 {
 	const ColumnNullable * col = typeid_cast<const ColumnNullable *>(&column);
 	if (col == nullptr)
 		throw Exception{"Discrepancy between data type and column type", ErrorCodes::LOGICAL_ERROR};
 
 	const ColumnUInt8 & content = static_cast<const ColumnUInt8 &>(*(col->getNullValuesByteMap().get()));
-	nested_data_type.get()->serializeTextJSON(*(col->getNestedColumn().get()), row_num, ostr, &content.getData());
+	const auto & null_map = content.getData();
+
+	if (isNullValue(&null_map, row_num))
+		writeCString(NullSymbol::JSON::name, ostr);
+	else
+		nested_data_type.get()->serializeTextJSON(*(col->getNestedColumn().get()), row_num, ostr);
 }
 
-void DataTypeNullable::deserializeTextJSONImpl(IColumn & column, ReadBuffer & istr,
-	NullValuesByteMap * null_map) const
+void DataTypeNullable::deserializeTextJSON(IColumn & column, ReadBuffer & istr) const
 {
 	ColumnNullable * col = typeid_cast<ColumnNullable *>(&column);
 	if (col == nullptr)
 		throw Exception{"Discrepancy between data type and column type", ErrorCodes::LOGICAL_ERROR};
 
 	ColumnUInt8 & content = static_cast<ColumnUInt8 &>(*(col->getNullValuesByteMap().get()));
-	nested_data_type.get()->deserializeTextJSON(*(col->getNestedColumn().get()), istr, &content.getData());
+	auto & null_map = content.getData();
+
+	if (NullSymbol::Deserializer<NullSymbol::JSON>::execute(column, istr, &null_map))
+		col->insertDefault();
+	else
+		nested_data_type.get()->deserializeTextJSON(*(col->getNestedColumn().get()), istr);
 }
 
 void DataTypeNullable::serializeTextXML(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
diff --git a/dbms/src/DataTypes/DataTypeString.cpp b/dbms/src/DataTypes/DataTypeString.cpp
index f416927a008..8a0f6199d53 100644
--- a/dbms/src/DataTypes/DataTypeString.cpp
+++ b/dbms/src/DataTypes/DataTypeString.cpp
@@ -250,16 +250,6 @@ static inline void read(IColumn & column, ReadBuffer & istr, Reader && reader)
 	}
 }
 
-void insertEmptyString(IColumn & column)
-{
-	ColumnString & column_string = static_cast<ColumnString &>(column);
-	ColumnString::Chars_t & data = column_string.getChars();
-	ColumnString::Offsets_t & offsets = column_string.getOffsets();
-
-	data.push_back(0);
-	offsets.push_back(data.size());
-}
-
 }
 
 void DataTypeString::deserializeTextEscaped(IColumn & column, ReadBuffer & istr) const
@@ -280,23 +270,15 @@ void DataTypeString::deserializeTextQuoted(IColumn & column, ReadBuffer & istr)
 }
 
 
-void DataTypeString::serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-	const NullValuesByteMap * null_map) const
+void DataTypeString::serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
 {
-	if (isNullValue(null_map, row_num))
-		writeCString(NullSymbol::JSON::name, ostr);
-	else
-		writeJSONString(static_cast<const ColumnString &>(column).getDataAt(row_num), ostr);
+	writeJSONString(static_cast<const ColumnString &>(column).getDataAt(row_num), ostr);
 }
 
 
-void DataTypeString::deserializeTextJSONImpl(IColumn & column, ReadBuffer & istr,
-	NullValuesByteMap * null_map) const
+void DataTypeString::deserializeTextJSON(IColumn & column, ReadBuffer & istr) const
 {
-	if (NullSymbol::Deserializer<NullSymbol::JSON>::execute(column, istr, null_map))
-		insertEmptyString(column);
-	else
-		read(column, istr, [&](ColumnString::Chars_t & data) { readJSONStringInto(data, istr); });
+	read(column, istr, [&](ColumnString::Chars_t & data) { readJSONStringInto(data, istr); });
 }
 
 
@@ -306,23 +288,15 @@ void DataTypeString::serializeTextXML(const IColumn & column, size_t row_num, Wr
 }
 
 
-void DataTypeString::serializeTextCSVImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-	const NullValuesByteMap * null_map) const
+void DataTypeString::serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
 {
-	if (isNullValue(null_map, row_num))
-		writeCString(NullSymbol::CSV::name, ostr);
-	else
-		writeCSVString<>(static_cast<const ColumnString &>(column).getDataAt(row_num), ostr);
+	writeCSVString<>(static_cast<const ColumnString &>(column).getDataAt(row_num), ostr);
 }
 
 
-void DataTypeString::deserializeTextCSVImpl(IColumn & column, ReadBuffer & istr, const char delimiter,
-	NullValuesByteMap * null_map) const
+void DataTypeString::deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const
 {
-	if (NullSymbol::Deserializer<NullSymbol::CSV>::execute(column, istr, null_map))
-		insertEmptyString(column);
-	else
-		read(column, istr, [&](ColumnString::Chars_t & data) { readCSVStringInto(data, istr); });
+	read(column, istr, [&](ColumnString::Chars_t & data) { readCSVStringInto(data, istr); });
 }
 
 
diff --git a/dbms/src/DataTypes/DataTypeTuple.cpp b/dbms/src/DataTypes/DataTypeTuple.cpp
index 35ff1ece2db..55e52b6be1d 100644
--- a/dbms/src/DataTypes/DataTypeTuple.cpp
+++ b/dbms/src/DataTypes/DataTypeTuple.cpp
@@ -145,46 +145,36 @@ void DataTypeTuple::deserializeTextQuoted(IColumn & column, ReadBuffer & istr) c
 	deserializeText(column, istr);
 }
 
-void DataTypeTuple::serializeTextJSONImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-	const NullValuesByteMap * null_map) const
+void DataTypeTuple::serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
 {
-	if (isNullValue(null_map, row_num))
-		writeCString(NullSymbol::JSON::name, ostr);
-	else
+	writeChar('[', ostr);
+	for (const auto i : ext::range(0, ext::size(elems)))
 	{
-		writeChar('[', ostr);
-		for (const auto i : ext::range(0, ext::size(elems)))
-		{
-			if (i != 0)
-				writeChar(',', ostr);
-			elems[i]->serializeTextJSON(extractElementColumn(column, i), row_num, ostr, null_map);
-		}
-		writeChar(']', ostr);
+		if (i != 0)
+			writeChar(',', ostr);
+		elems[i]->serializeTextJSON(extractElementColumn(column, i), row_num, ostr);
 	}
+	writeChar(']', ostr);
 }
 
-void DataTypeTuple::deserializeTextJSONImpl(IColumn & column, ReadBuffer & istr,
-	NullValuesByteMap * null_map) const
+void DataTypeTuple::deserializeTextJSON(IColumn & column, ReadBuffer & istr) const
 {
-	if (!NullSymbol::Deserializer<NullSymbol::JSON>::execute(column, istr, null_map))
+	const size_t size = elems.size();
+	assertChar('[', istr);
+
+	deserializeSafe(elems, column, istr, [&]
 	{
-		const size_t size = elems.size();
-		assertChar('[', istr);
-
-		deserializeSafe(elems, column, istr, [&]
+		for (const auto i : ext::range(0, size))
 		{
-			for (const auto i : ext::range(0, size))
-			{
-				skipWhitespaceIfAny(istr);
-				if (i != 0)
-					assertChar(',', istr);
-				elems[i]->deserializeTextJSON(extractElementColumn(column, i), istr, null_map);
-			}
-		});
+			skipWhitespaceIfAny(istr);
+			if (i != 0)
+				assertChar(',', istr);
+			elems[i]->deserializeTextJSON(extractElementColumn(column, i), istr);
+		}
+	});
 
-		skipWhitespaceIfAny(istr);
-		assertChar(']', istr);
-	}
+	skipWhitespaceIfAny(istr);
+	assertChar(']', istr);
 }
 
 void DataTypeTuple::serializeTextXML(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
@@ -199,42 +189,32 @@ void DataTypeTuple::serializeTextXML(const IColumn & column, size_t row_num, Wri
 	writeCString("</tuple>", ostr);
 }
 
-void DataTypeTuple::serializeTextCSVImpl(const IColumn & column, size_t row_num, WriteBuffer & ostr,
-	const NullValuesByteMap * null_map) const
+void DataTypeTuple::serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr) const
 {
-	if (isNullValue(null_map, row_num))
-		writeCString(NullSymbol::CSV::name, ostr);
-	else
+	for (const auto i : ext::range(0, ext::size(elems)))
 	{
-		for (const auto i : ext::range(0, ext::size(elems)))
-		{
-			if (i != 0)
-				writeChar(',', ostr);
-			elems[i]->serializeTextCSV(extractElementColumn(column, i), row_num, ostr, null_map);
-		}
+		if (i != 0)
+			writeChar(',', ostr);
+		elems[i]->serializeTextCSV(extractElementColumn(column, i), row_num, ostr);
 	}
 }
 
-void DataTypeTuple::deserializeTextCSVImpl(IColumn & column, ReadBuffer & istr, const char delimiter,
-	NullValuesByteMap * null_map) const
+void DataTypeTuple::deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const
 {
-	if (!NullSymbol::Deserializer<NullSymbol::JSON>::execute(column, istr, null_map))
+	deserializeSafe(elems, column, istr, [&]
 	{
-		deserializeSafe(elems, column, istr, [&]
+		const size_t size = elems.size();
+		for (const auto i : ext::range(0, size))
 		{
-			const size_t size = elems.size();
-			for (const auto i : ext::range(0, size))
+			if (i != 0)
 			{
-				if (i != 0)
-				{
-					skipWhitespaceIfAny(istr);
-					assertChar(delimiter, istr);
-					skipWhitespaceIfAny(istr);
-				}
-				elems[i]->deserializeTextCSV(extractElementColumn(column, i), istr, delimiter, null_map);
+				skipWhitespaceIfAny(istr);
+				assertChar(delimiter, istr);
+				skipWhitespaceIfAny(istr);
 			}
-		});
-	}
+			elems[i]->deserializeTextCSV(extractElementColumn(column, i), istr, delimiter);
+		}
+	});
 }
 
 void DataTypeTuple::serializeBinary(const IColumn & column, WriteBuffer & ostr, size_t offset, size_t limit) const