Cloud databases: development [#METR-19998].

dbms/include/DB/Storages/StorageCloud.h

@@ -0,0 +1,71 @@
+#pragma once
+
+#include <DB/Storages/IStorage.h>
+#include <DB/Databases/IDatabase.h>
+
+
+namespace DB
+{
+
+class DatabaseCloud;
+
+
+/** Таблица, представляющая собой объединение произвольного количества других таблиц.
+  * У всех таблиц должна быть одинаковая структура.
+  */
+class StorageCloud : public IStorage
+{
+public:
+	static StoragePtr create(
+		const std::string & name_,
+		NamesAndTypesListPtr columns_,
+		const NamesAndTypesList & materialized_columns_,
+		const NamesAndTypesList & alias_columns_,
+		const ColumnDefaults & column_defaults_);
+
+	std::string getName() const override { return "Cloud"; }
+	std::string getTableName() const override { return name; }
+
+	/// Проверка откладывается до метода read. Там проверяется поддержка PREWHERE у использующихся таблиц.
+	bool supportsSampling() const override { return true; }
+	bool supportsPrewhere() const override { return true; }
+	bool supportsFinal() 	const override { return true; }
+	bool supportsIndexForIn() const override { return true; }
+
+	const NamesAndTypesList & getColumnsListImpl() const override { return *columns; }
+	NameAndTypePair getColumn(const String & column_name) const override;
+	bool hasColumn(const String & column_name) const override;
+
+	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;
+
+	void drop() override {}
+
+	void rename(const String & new_path_to_db, const String & new_database_name, const String & new_table_name) override
+	{
+		name = new_table_name;
+	}
+
+	//void alter(const AlterCommands & params, const String & database_name, const String & table_name, const Context & context) override;
+
+private:
+	String name;
+	NamesAndTypesListPtr columns;
+
+	std::weak_ptr<IDatabase> database;
+
+	StorageCloud(
+		const std::string & name_,
+		NamesAndTypesListPtr columns_,
+		const NamesAndTypesList & materialized_columns_,
+		const NamesAndTypesList & alias_columns_,
+		const ColumnDefaults & column_defaults_);
+};
+
+}

dbms/src/Storages/StorageCloud.cpp

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+#include <DB/Storages/StorageCloud.h>
+#include <DB/Databases/DatabaseCloud.h>
+
+
+namespace DB
+{
+
+namespace ErrorCodes
+{
+	extern const int LOGICAL_ERROR;
+}
+
+
+void StorageCloud::drop()
+{
+	DatabasePtr owned_db = database.lock();
+	if (!owned_db)
+		throw Exception("DatabaseCloud is detached", ErrorCodes::LOGICAL_ERROR);
+
+	DatabaseCloud & db = static_cast<DatabaseCloud &>(*owned_db);
+
+	
+}
+
+}