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#pragma once
#include "clickhouse_config.h"
#if USE_HDFS
#include <mutex>
#include <Databases/IDatabase.h>
#include <Parsers/IAST.h>
#include <Storages/IStorage_fwd.h>
#include <base/types.h>
namespace DB
{
class Context;
/**
* DatabaseHDFS allows to interact with files stored on the file system.
* Uses TableFunctionHDFS to implicitly load file when a user requests the table,
* and provides read-only access to the data in the file.
* Tables are cached inside the database for quick access.
*/
class DatabaseHDFS : public IDatabase, protected WithContext
{
public:
DatabaseHDFS(const String & name, const String & source_url, ContextPtr context);
String getEngineName() const override { return "S3"; }
bool isTableExist(const String & name, ContextPtr context) const override;
StoragePtr getTable(const String & name, ContextPtr context) const override;
StoragePtr tryGetTable(const String & name, ContextPtr context) const override;
bool shouldBeEmptyOnDetach() const override { return false; } /// Contains only temporary tables.
bool empty() const override;
bool isReadOnly() const override { return true; }
ASTPtr getCreateDatabaseQuery() const override;
void shutdown() override;
std::vector<std::pair<ASTPtr, StoragePtr>> getTablesForBackup(const FilterByNameFunction &, const ContextPtr &) const override;
DatabaseTablesIteratorPtr getTablesIterator(ContextPtr, const FilterByNameFunction &) const override;
protected:
StoragePtr getTableImpl(const String & name, ContextPtr context) const;
void addTable(const std::string & table_name, StoragePtr table_storage) const;
bool checkUrl(const std::string & url, ContextPtr context_, bool throw_on_error) const;
std::string getTablePath(const std::string & table_name) const;
private:
const String source;
mutable Tables loaded_tables TSA_GUARDED_BY(mutex);
Poco::Logger * log;
};
}
#endif
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