ClickHouse/dbms/src/Storages/StorageDistributed.h
2020-02-20 17:40:58 +03:00

192 lines
6.7 KiB
C++

#pragma once
#include <ext/shared_ptr_helper.h>
#include <Storages/IStorage.h>
#include <Common/SimpleIncrement.h>
#include <Client/ConnectionPool.h>
#include <Client/ConnectionPoolWithFailover.h>
#include <Core/Settings.h>
#include <Interpreters/Cluster.h>
#include <Parsers/ASTFunction.h>
#include <common/logger_useful.h>
#include <Common/ActionBlocker.h>
namespace DB
{
class Context;
class StorageDistributedDirectoryMonitor;
class Volume;
using VolumePtr = std::shared_ptr<Volume>;
class ExpressionActions;
using ExpressionActionsPtr = std::shared_ptr<ExpressionActions>;
/** A distributed table that resides on multiple servers.
* Uses data from the specified database and tables on each server.
*
* You can pass one address, not several.
* In this case, the table can be considered remote, rather than distributed.
*/
class StorageDistributed : public ext::shared_ptr_helper<StorageDistributed>, public IStorage
{
friend struct ext::shared_ptr_helper<StorageDistributed>;
friend class DistributedBlockOutputStream;
friend class StorageDistributedDirectoryMonitor;
public:
~StorageDistributed() override;
static StoragePtr createWithOwnCluster(
const StorageID & table_id_,
const ColumnsDescription & columns_,
const String & remote_database_, /// database on remote servers.
const String & remote_table_, /// The name of the table on the remote servers.
ClusterPtr owned_cluster_,
const Context & context_);
static StoragePtr createWithOwnCluster(
const StorageID & table_id_,
const ColumnsDescription & columns_,
ASTPtr & remote_table_function_ptr_, /// Table function ptr.
ClusterPtr & owned_cluster_,
const Context & context_);
std::string getName() const override { return "Distributed"; }
bool supportsSampling() const override { return true; }
bool supportsFinal() const override { return true; }
bool supportsPrewhere() const override { return true; }
NameAndTypePair getColumn(const String & column_name) const override;
bool hasColumn(const String & column_name) const override;
bool isRemote() const override { return true; }
QueryProcessingStage::Enum getQueryProcessingStage(const Context & context) const override;
QueryProcessingStage::Enum getQueryProcessingStage(const Context & context, const ClusterPtr & cluster) const;
Pipes read(
const Names & column_names,
const SelectQueryInfo & query_info,
const Context & context,
QueryProcessingStage::Enum processed_stage,
size_t max_block_size,
unsigned num_streams) override;
BlockOutputStreamPtr write(const ASTPtr & query, const Context & context) override;
void drop(TableStructureWriteLockHolder &) override {}
/// Removes temporary data in local filesystem.
void truncate(const ASTPtr &, const Context &, TableStructureWriteLockHolder &) override;
void rename(const String & new_path_to_table_data, const String & new_database_name, const String & new_table_name, TableStructureWriteLockHolder &) override;
void renameOnDisk(const String & new_path_to_table_data);
void checkAlterIsPossible(const AlterCommands & commands, const Settings & /* settings */) override;
/// in the sub-tables, you need to manually add and delete columns
/// the structure of the sub-table is not checked
void alter(const AlterCommands & params, const Context & context, TableStructureWriteLockHolder & table_lock_holder) override;
void startup() override;
void shutdown() override;
Strings getDataPaths() const override;
const ExpressionActionsPtr & getShardingKeyExpr() const { return sharding_key_expr; }
const String & getShardingKeyColumnName() const { return sharding_key_column_name; }
size_t getShardCount() const;
std::pair<const std::string &, const std::string &> getPath();
std::string getRemoteDatabaseName() const { return remote_database; }
std::string getRemoteTableName() const { return remote_table; }
std::string getClusterName() const { return cluster_name; } /// Returns empty string if tables is used by TableFunctionRemote
/// create directory monitors for each existing subdirectory
void createDirectoryMonitors(const std::string & disk);
/// ensure directory monitor thread and connectoin pool creation by disk and subdirectory name
void requireDirectoryMonitor(const std::string & disk, const std::string & name);
void flushClusterNodesAllData();
ClusterPtr getCluster() const;
ActionLock getActionLock(StorageActionBlockType type) override;
String remote_database;
String remote_table;
ASTPtr remote_table_function_ptr;
Context global_context;
Logger * log = &Logger::get("StorageDistributed");
/// Used to implement TableFunctionRemote.
std::shared_ptr<Cluster> owned_cluster;
/// Is empty if this storage implements TableFunctionRemote.
const String cluster_name;
bool has_sharding_key;
ExpressionActionsPtr sharding_key_expr;
String sharding_key_column_name;
/// Used for global monotonic ordering of files to send.
SimpleIncrement file_names_increment;
ActionBlocker monitors_blocker;
protected:
StorageDistributed(
const StorageID & id_,
const ColumnsDescription & columns_,
const ConstraintsDescription & constraints_,
const String & remote_database_,
const String & remote_table_,
const String & cluster_name_,
const Context & context_,
const ASTPtr & sharding_key_,
const String & storage_policy_,
const String & relative_data_path_,
bool attach_);
StorageDistributed(
const StorageID & id_,
const ColumnsDescription & columns_,
const ConstraintsDescription & constraints_,
ASTPtr remote_table_function_ptr_,
const String & cluster_name_,
const Context & context_,
const ASTPtr & sharding_key_,
const String & storage_policy_,
const String & relative_data_path_,
bool attach);
ClusterPtr skipUnusedShards(ClusterPtr cluster, const SelectQueryInfo & query_info);
void createStorage();
String storage_policy;
String relative_data_path;
/// Can be empty if relative_data_path is empty. In this case, a directory for the data to be sent is not created.
VolumePtr volume;
struct ClusterNodeData
{
std::unique_ptr<StorageDistributedDirectoryMonitor> directory_monitor;
ConnectionPoolPtr conneciton_pool;
void flushAllData();
void shutdownAndDropAllData();
};
std::unordered_map<std::string, ClusterNodeData> cluster_nodes_data;
std::mutex cluster_nodes_mutex;
};
}