Exemplo n.º 1
0
func (self *ShardData) getProcessor(querySpec *parser.QuerySpec, processor engine.Processor) (engine.Processor, error) {
	switch qt := querySpec.Query().Type(); qt {
	case parser.Delete, parser.DropSeries:
		return NilProcessor{}, nil
	case parser.Select:
		// continue
	default:
		panic(fmt.Errorf("Unexpected query type: %s", qt))
	}

	if querySpec.IsSinglePointQuery() {
		return engine.NewPassthroughEngine(processor, 1), nil
	}

	query := querySpec.SelectQuery()

	var err error
	// We should aggregate at the shard level
	if self.ShouldAggregateLocally(querySpec) {
		log.Debug("creating a query engine")
		processor, err = engine.NewQueryEngine(processor, query, nil)
		if err != nil {
			return nil, err
		}
		goto addFilter
	}

	// we shouldn't limit the queries if they have aggregates and aren't
	// aggregated locally, otherwise the aggregation result which happen
	// in the coordinator will get partial data and will be incorrect
	if query.HasAggregates() {
		log.Debug("creating a passthrough engine")
		processor = engine.NewPassthroughEngine(processor, 1000)
		goto addFilter
	}

	// This is an optimization so we don't send more data that we should
	// over the wire. The coordinator has its own Passthrough which does
	// the final limit.
	if l := query.Limit; l > 0 {
		log.Debug("creating a passthrough engine with limit")
		processor = engine.NewPassthroughEngineWithLimit(processor, 1000, query.Limit)
	}

addFilter:
	if query := querySpec.SelectQuery(); query != nil && query.GetFromClause().Type != parser.FromClauseInnerJoin {
		// Joins do their own filtering since we need to get all
		// points before filtering. This is due to the fact that some
		// where expressions will be difficult to compute before the
		// points are joined together, think where clause with
		// left.column = 'something' or right.column =
		// 'something_else'. We can't filter the individual series
		// separately. The filtering happens in merge.go:55

		processor = engine.NewFilteringEngine(query, processor)
	}
	return processor, nil
}
Exemplo n.º 2
0
func (self *CoordinatorImpl) getShardsAndProcessor(querySpec *parser.QuerySpec, writer SeriesWriter) ([]*cluster.ShardData, cluster.QueryProcessor, chan bool, error) {
	shards := self.clusterConfiguration.GetShardsForQuery(querySpec)
	shouldAggregateLocally := self.shouldAggregateLocally(shards, querySpec)

	var err error
	var processor cluster.QueryProcessor

	responseChan := make(chan *protocol.Response)
	seriesClosed := make(chan bool)

	selectQuery := querySpec.SelectQuery()
	if selectQuery != nil {
		if !shouldAggregateLocally {
			// if we should aggregate in the coordinator (i.e. aggregation
			// isn't happening locally at the shard level), create an engine
			processor, err = engine.NewQueryEngine(querySpec.SelectQuery(), responseChan)
		} else {
			// if we have a query with limit, then create an engine, or we can
			// make the passthrough limit aware
			processor = engine.NewPassthroughEngineWithLimit(responseChan, 100, selectQuery.Limit)
		}
	} else if !shouldAggregateLocally {
		processor = engine.NewPassthroughEngine(responseChan, 100)
	}

	if err != nil {
		return nil, nil, nil, err
	}

	if processor == nil {
		return shards, nil, nil, nil
	}

	go func() {
		for {
			response := <-responseChan

			if *response.Type == endStreamResponse || *response.Type == accessDeniedResponse {
				writer.Close()
				seriesClosed <- true
				return
			}
			if !(*response.Type == queryResponse && querySpec.IsExplainQuery()) {
				if response.Series != nil && len(response.Series.Points) > 0 {
					writer.Write(response.Series)
				}
			}
		}
	}()

	return shards, processor, seriesClosed, nil
}
Exemplo n.º 3
0
func (self *ShardData) deleteDataLocally(querySpec *parser.QuerySpec) (<-chan *p.Response, error) {
	localResponses := make(chan *p.Response, 1)

	// this doesn't really apply at this point since destructive queries don't output anything, but it may later
	maxPointsFromDestructiveQuery := 1000
	processor := engine.NewPassthroughEngine(localResponses, maxPointsFromDestructiveQuery)
	shard, err := self.store.GetOrCreateShard(self.id)
	if err != nil {
		return nil, err
	}
	defer self.store.ReturnShard(self.id)
	err = shard.Query(querySpec, processor)
	processor.Close()
	return localResponses, err
}
Exemplo n.º 4
0
func (dm *DataMigrator) migrateDatabaseInShard(database string, shard *LevelDbShard) error {
	log.Info("Migrating database %s for shard", database)
	seriesNames := shard.GetSeriesForDatabase(database)
	log.Info("Migrating %d series", len(seriesNames))

	admin := dm.clusterConfig.GetClusterAdmin(dm.clusterConfig.GetClusterAdmins()[0])
	pointCount := 0
	for _, series := range seriesNames {
		q, err := parser.ParseQuery(fmt.Sprintf("select * from \"%s\"", series))
		if err != nil {
			log.Error("Problem migrating series %s", series)
			continue
		}
		query := q[0]
		seriesChan := make(chan *protocol.Response)
		queryEngine := engine.NewPassthroughEngine(seriesChan, 2000)
		querySpec := parser.NewQuerySpec(admin, database, query)
		go func() {
			err := shard.Query(querySpec, queryEngine)
			if err != nil {
				log.Error("Error migrating %s", err.Error())
			}
			queryEngine.Close()
			seriesChan <- &protocol.Response{Type: &endStreamResponse}
		}()
		for {
			response := <-seriesChan
			if *response.Type == endStreamResponse {
				break
			}
			err := dm.coord.WriteSeriesData(admin, database, []*protocol.Series{response.Series})
			if err != nil {
				log.Error("Writing Series data: %s", err.Error())
			}
			pointCount += len(response.Series.Points)
			if pointCount > POINT_COUNT_TO_PAUSE {
				pointCount = 0
				time.Sleep(dm.pauseTime)
			}
		}
	}
	log.Info("Done migrating %s for shard", database)
	return nil
}
Exemplo n.º 5
0
func (self *ShardData) Query(querySpec *parser.QuerySpec, response chan *p.Response) {
	log.Debug("QUERY: shard %d, query '%s'", self.Id(), querySpec.GetQueryString())
	defer common.RecoverFunc(querySpec.Database(), querySpec.GetQueryString(), func(err interface{}) {
		response <- &p.Response{Type: &endStreamResponse, ErrorMessage: p.String(fmt.Sprintf("%s", err))}
	})

	// This is only for queries that are deletes or drops. They need to be sent everywhere as opposed to just the local or one of the remote shards.
	// But this boolean should only be set to true on the server that receives the initial query.
	if querySpec.RunAgainstAllServersInShard {
		if querySpec.IsDeleteFromSeriesQuery() {
			self.logAndHandleDeleteQuery(querySpec, response)
		} else if querySpec.IsDropSeriesQuery() {
			self.logAndHandleDropSeriesQuery(querySpec, response)
		}
	}

	if self.IsLocal {
		var processor QueryProcessor
		var err error

		if querySpec.IsListSeriesQuery() {
			processor = engine.NewListSeriesEngine(response)
		} else if querySpec.IsDeleteFromSeriesQuery() || querySpec.IsDropSeriesQuery() || querySpec.IsSinglePointQuery() {
			maxDeleteResults := 10000
			processor = engine.NewPassthroughEngine(response, maxDeleteResults)
		} else {
			query := querySpec.SelectQuery()
			if self.ShouldAggregateLocally(querySpec) {
				log.Debug("creating a query engine")
				processor, err = engine.NewQueryEngine(query, response)
				if err != nil {
					response <- &p.Response{Type: &endStreamResponse, ErrorMessage: p.String(err.Error())}
					log.Error("Error while creating engine: %s", err)
					return
				}
				processor.SetShardInfo(int(self.Id()), self.IsLocal)
			} else if query.HasAggregates() {
				maxPointsToBufferBeforeSending := 1000
				log.Debug("creating a passthrough engine")
				processor = engine.NewPassthroughEngine(response, maxPointsToBufferBeforeSending)
			} else {
				maxPointsToBufferBeforeSending := 1000
				log.Debug("creating a passthrough engine with limit")
				processor = engine.NewPassthroughEngineWithLimit(response, maxPointsToBufferBeforeSending, query.Limit)
			}

			if query.GetFromClause().Type != parser.FromClauseInnerJoin {
				// Joins do their own filtering since we need to get all
				// points before filtering. This is due to the fact that some
				// where expressions will be difficult to compute before the
				// points are joined together, think where clause with
				// left.column = 'something' or right.column =
				// 'something_else'. We can't filter the individual series
				// separately. The filtering happens in merge.go:55

				processor = engine.NewFilteringEngine(query, processor)
			}
		}
		shard, err := self.store.GetOrCreateShard(self.id)
		if err != nil {
			response <- &p.Response{Type: &endStreamResponse, ErrorMessage: p.String(err.Error())}
			log.Error("Error while getting shards: %s", err)
			return
		}
		defer self.store.ReturnShard(self.id)
		err = shard.Query(querySpec, processor)
		// if we call Close() in case of an error it will mask the error
		if err != nil {
			response <- &p.Response{Type: &endStreamResponse, ErrorMessage: p.String(err.Error())}
			return
		}
		processor.Close()
		response <- &p.Response{Type: &endStreamResponse}
		return
	}

	if server := self.randomHealthyServer(); server != nil {
		log.Debug("Querying server %d for shard %d", server.GetId(), self.Id())
		request := self.createRequest(querySpec)
		server.MakeRequest(request, response)
		return
	}

	message := fmt.Sprintf("No servers up to query shard %d", self.id)
	response <- &p.Response{Type: &endStreamResponse, ErrorMessage: &message}
	log.Error(message)
}