#include "Storages/IStorageCluster.h" #include "Common/Exception.h" #include "Core/QueryProcessingStage.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include namespace DB { IStorageCluster::IStorageCluster( const String & cluster_name_, const StorageID & table_id_, Poco::Logger * log_, bool structure_argument_was_provided_) : IStorage(table_id_) , log(log_) , cluster_name(cluster_name_) , structure_argument_was_provided(structure_argument_was_provided_) { } /// The code executes on initiator Pipe IStorageCluster::read( const Names & column_names, const StorageSnapshotPtr & storage_snapshot, SelectQueryInfo & query_info, ContextPtr context, QueryProcessingStage::Enum processed_stage, size_t /*max_block_size*/, size_t /*num_streams*/) { updateBeforeRead(context); auto cluster = getCluster(context); auto extension = getTaskIteratorExtension(query_info.query, context); /// Calculate the header. This is significant, because some columns could be thrown away in some cases like query with count(*) Block sample_block; ASTPtr query_to_send = query_info.query; if (context->getSettingsRef().allow_experimental_analyzer) { sample_block = InterpreterSelectQueryAnalyzer::getSampleBlock(query_info.query, context, SelectQueryOptions(processed_stage)); } else { auto interpreter = InterpreterSelectQuery(query_info.query, context, SelectQueryOptions(processed_stage).analyze()); sample_block = interpreter.getSampleBlock(); query_to_send = interpreter.getQueryInfo().query->clone(); } const Scalars & scalars = context->hasQueryContext() ? context->getQueryContext()->getScalars() : Scalars{}; Pipes pipes; const bool add_agg_info = processed_stage == QueryProcessingStage::WithMergeableState; if (!structure_argument_was_provided) addColumnsStructureToQuery(query_to_send, storage_snapshot->metadata->getColumns().getAll().toNamesAndTypesDescription(), context); RestoreQualifiedNamesVisitor::Data data; data.distributed_table = DatabaseAndTableWithAlias(*getTableExpression(query_info.query->as(), 0)); data.remote_table.database = context->getCurrentDatabase(); data.remote_table.table = getName(); RestoreQualifiedNamesVisitor(data).visit(query_to_send); AddDefaultDatabaseVisitor visitor(context, context->getCurrentDatabase(), /* only_replace_current_database_function_= */false, /* only_replace_in_join_= */true); visitor.visit(query_to_send); auto new_context = updateSettings(context, context->getSettingsRef()); const auto & current_settings = new_context->getSettingsRef(); auto timeouts = ConnectionTimeouts::getTCPTimeoutsWithFailover(current_settings); for (const auto & shard_info : cluster->getShardsInfo()) { auto try_results = shard_info.pool->getMany(timeouts, current_settings, PoolMode::GET_MANY); for (auto & try_result : try_results) { auto remote_query_executor = std::make_shared( std::vector{try_result}, queryToString(query_to_send), sample_block, new_context, /*throttler=*/nullptr, scalars, Tables(), processed_stage, extension); remote_query_executor->setLogger(log); pipes.emplace_back(std::make_shared(remote_query_executor, add_agg_info, false, false)); } } storage_snapshot->check(column_names); return Pipe::unitePipes(std::move(pipes)); } QueryProcessingStage::Enum IStorageCluster::getQueryProcessingStage( ContextPtr context, QueryProcessingStage::Enum to_stage, const StorageSnapshotPtr &, SelectQueryInfo &) const { /// Initiator executes query on remote node. if (context->getClientInfo().query_kind == ClientInfo::QueryKind::INITIAL_QUERY) if (to_stage >= QueryProcessingStage::Enum::WithMergeableState) return QueryProcessingStage::Enum::WithMergeableState; /// Follower just reads the data. return QueryProcessingStage::Enum::FetchColumns; } ContextPtr IStorageCluster::updateSettings(ContextPtr context, const Settings & settings) { Settings new_settings = settings; /// Cluster table functions should always skip unavailable shards. new_settings.skip_unavailable_shards = true; auto new_context = Context::createCopy(context); new_context->setSettings(new_settings); return new_context; } ClusterPtr IStorageCluster::getCluster(ContextPtr context) const { return context->getCluster(cluster_name)->getClusterWithReplicasAsShards(context->getSettingsRef()); } }