#pragma once #include #include #include #include #include #include #include #include #include #include #include #include namespace DB { struct Settings; class Context; class IVolume; using VolumePtr = std::shared_ptr; class IDisk; using DiskPtr = std::shared_ptr; class ExpressionActions; using ExpressionActionsPtr = std::shared_ptr; /** 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 final : public shared_ptr_helper, public IStorage, WithContext { friend struct shared_ptr_helper; friend class DistributedSink; friend class StorageDistributedDirectoryMonitor; friend class StorageSystemDistributionQueue; public: ~StorageDistributed() override; 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; } bool supportsSubcolumns() const override { return true; } StoragePolicyPtr getStoragePolicy() const override; bool isRemote() const override { return true; } QueryProcessingStage::Enum getQueryProcessingStage(ContextPtr, QueryProcessingStage::Enum, const StorageMetadataPtr &, SelectQueryInfo &) const override; Pipe read( const Names & column_names, const StorageMetadataPtr & /*metadata_snapshot*/, SelectQueryInfo & query_info, ContextPtr context, QueryProcessingStage::Enum processed_stage, size_t max_block_size, unsigned num_streams) override; void read( QueryPlan & query_plan, const Names & column_names, const StorageMetadataPtr & metadata_snapshot, SelectQueryInfo & query_info, ContextPtr context, QueryProcessingStage::Enum processed_stage, size_t /*max_block_size*/, unsigned /*num_streams*/) override; bool supportsParallelInsert() const override { return true; } std::optional totalBytes(const Settings &) const override; SinkToStoragePtr write(const ASTPtr & query, const StorageMetadataPtr & /*metadata_snapshot*/, ContextPtr context) override; QueryPipelineBuilderPtr distributedWrite(const ASTInsertQuery & query, ContextPtr context) override; /// Removes temporary data in local filesystem. void truncate(const ASTPtr &, const StorageMetadataPtr &, ContextPtr, TableExclusiveLockHolder &) override; void rename(const String & new_path_to_table_data, const StorageID & new_table_id) override; void checkAlterIsPossible(const AlterCommands & commands, ContextPtr context) const 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, ContextPtr context, AlterLockHolder & table_lock_holder) override; void startup() override; void shutdown() override; void flush() override; void drop() override; bool storesDataOnDisk() const override { return data_volume != nullptr; } Strings getDataPaths() const override; ActionLock getActionLock(StorageActionBlockType type) override; NamesAndTypesList getVirtuals() const override; /// Used by InterpreterInsertQuery std::string getRemoteDatabaseName() const { return remote_database; } std::string getRemoteTableName() const { return remote_table; } /// Returns empty string if tables is used by TableFunctionRemote std::string getClusterName() const { return cluster_name; } ClusterPtr getCluster() const; /// Used by InterpreterSystemQuery void flushClusterNodesAllData(ContextPtr context); /// Used by ClusterCopier size_t getShardCount() const; private: StorageDistributed( const StorageID & id_, const ColumnsDescription & columns_, const ConstraintsDescription & constraints_, const String & comment, const String & remote_database_, const String & remote_table_, const String & cluster_name_, ContextPtr context_, const ASTPtr & sharding_key_, const String & storage_policy_name_, const String & relative_data_path_, const DistributedSettings & distributed_settings_, bool attach_, ClusterPtr owned_cluster_ = {}, ASTPtr remote_table_function_ptr_ = {}); StorageDistributed( const StorageID & id_, const ColumnsDescription & columns_, const ConstraintsDescription & constraints_, ASTPtr remote_table_function_ptr_, const String & cluster_name_, ContextPtr context_, const ASTPtr & sharding_key_, const String & storage_policy_name_, const String & relative_data_path_, const DistributedSettings & distributed_settings_, bool attach, ClusterPtr owned_cluster_ = {}); void renameOnDisk(const String & new_path_to_table_data); const ExpressionActionsPtr & getShardingKeyExpr() const { return sharding_key_expr; } const String & getShardingKeyColumnName() const { return sharding_key_column_name; } const String & getRelativeDataPath() const { return relative_data_path; } /// create directory monitors for each existing subdirectory void createDirectoryMonitors(const DiskPtr & disk); /// ensure directory monitor thread and connectoin pool creation by disk and subdirectory name StorageDistributedDirectoryMonitor & requireDirectoryMonitor(const DiskPtr & disk, const std::string & name, bool startup); /// Return list of metrics for all created monitors /// (note that monitors are created lazily, i.e. until at least one INSERT executed) /// /// Used by StorageSystemDistributionQueue std::vector getDirectoryMonitorsStatuses() const; static IColumn::Selector createSelector(ClusterPtr cluster, const ColumnWithTypeAndName & result); /// Apply the following settings: /// - optimize_skip_unused_shards /// - force_optimize_skip_unused_shards ClusterPtr getOptimizedCluster(ContextPtr, const StorageMetadataPtr & metadata_snapshot, const ASTPtr & query_ptr) const; ClusterPtr skipUnusedShards( ClusterPtr cluster, const ASTPtr & query_ptr, const StorageMetadataPtr & metadata_snapshot, ContextPtr context) const; /// This method returns optimal query processing stage. /// /// Here is the list of stages (from the less optimal to more optimal): /// - WithMergeableState /// - WithMergeableStateAfterAggregation /// - WithMergeableStateAfterAggregationAndLimit /// - Complete /// /// Some simple queries w/o GROUP BY/DISTINCT can use more optimal stage. /// /// Also in case of optimize_distributed_group_by_sharding_key=1 the queries /// with GROUP BY/DISTINCT sharding_key can also use more optimal stage. /// (see also optimize_skip_unused_shards/allow_nondeterministic_optimize_skip_unused_shards) /// /// @return QueryProcessingStage or empty std::optoinal /// (in this case regular WithMergeableState should be used) std::optional getOptimizedQueryProcessingStage(const SelectQueryInfo & query_info, const Settings & settings) const; size_t getRandomShardIndex(const Cluster::ShardsInfo & shards); const DistributedSettings & getDistributedSettingsRef() const { return distributed_settings; } void delayInsertOrThrowIfNeeded() const; String remote_database; String remote_table; ASTPtr remote_table_function_ptr; Poco::Logger * log; /// Used to implement TableFunctionRemote. std::shared_ptr owned_cluster; /// Is empty if this storage implements TableFunctionRemote. const String cluster_name; bool has_sharding_key; bool sharding_key_is_deterministic = false; 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; 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. StoragePolicyPtr storage_policy; /// The main volume to store data. /// Storage policy may have several configured volumes, but second and other volumes are used for parts movement in MergeTree engine. /// For Distributed engine such configuration doesn't make sense and only the first (main) volume will be used to store data. /// Other volumes will be ignored. It's needed to allow using the same multi-volume policy both for Distributed and other engines. VolumePtr data_volume; DistributedSettings distributed_settings; struct ClusterNodeData { std::shared_ptr directory_monitor; ConnectionPoolPtr connection_pool; }; std::unordered_map cluster_nodes_data; mutable std::mutex cluster_nodes_mutex; // For random shard index generation mutable std::mutex rng_mutex; pcg64 rng; }; }