Java tutorial
/** * Copyright (C) 2014-2016 LinkedIn Corp. (pinot-core@linkedin.com) * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.linkedin.pinot.server.request; import com.google.common.base.Function; import com.google.common.util.concurrent.Futures; import com.google.common.util.concurrent.ListenableFuture; import com.linkedin.pinot.common.exception.QueryException; import com.linkedin.pinot.common.metrics.ServerMeter; import com.linkedin.pinot.common.metrics.ServerMetrics; import com.linkedin.pinot.common.metrics.ServerQueryPhase; import com.linkedin.pinot.common.query.QueryRequest; import com.linkedin.pinot.common.query.context.TimerContext; import com.linkedin.pinot.common.request.InstanceRequest; import com.linkedin.pinot.common.utils.DataTable; import com.linkedin.pinot.core.common.datatable.DataTableImplV2; import com.linkedin.pinot.core.query.scheduler.QueryScheduler; import com.linkedin.pinot.serde.SerDe; import com.linkedin.pinot.transport.netty.NettyServer; import io.netty.buffer.ByteBuf; import io.netty.channel.ChannelHandlerContext; import java.net.InetSocketAddress; import javax.annotation.Nullable; import org.apache.thrift.protocol.TCompactProtocol; import org.slf4j.Logger; import org.slf4j.LoggerFactory; public class ScheduledRequestHandler implements NettyServer.RequestHandler { private static final Logger LOGGER = LoggerFactory.getLogger(ScheduledRequestHandler.class); private final ServerMetrics serverMetrics; private final QueryScheduler queryScheduler; public ScheduledRequestHandler(QueryScheduler queryScheduler, ServerMetrics serverMetrics) { this.queryScheduler = queryScheduler; this.serverMetrics = serverMetrics; } @Override public ListenableFuture<byte[]> processRequest(ChannelHandlerContext channelHandlerContext, ByteBuf request) { final long queryStartTimeNs = System.nanoTime(); serverMetrics.addMeteredGlobalValue(ServerMeter.QUERIES, 1); LOGGER.debug("Processing request : {}", request); byte[] byteArray = new byte[request.readableBytes()]; request.readBytes(byteArray); SerDe serDe = new SerDe(new TCompactProtocol.Factory()); final InstanceRequest instanceRequest = new InstanceRequest(); if (!serDe.deserialize(instanceRequest, byteArray)) { LOGGER.error("Failed to deserialize query request from broker ip: {}", ((InetSocketAddress) channelHandlerContext.channel().remoteAddress()).getAddress() .getHostAddress()); DataTable result = new DataTableImplV2(); result.addException(QueryException.INTERNAL_ERROR); serverMetrics.addMeteredGlobalValue(ServerMeter.REQUEST_DESERIALIZATION_EXCEPTIONS, 1); QueryRequest queryRequest = new QueryRequest(null, serverMetrics); queryRequest.getTimerContext().setQueryArrivalTimeNs(queryStartTimeNs); return Futures.immediateFuture(serializeDataTable(queryRequest, result)); } final QueryRequest queryRequest = new QueryRequest(instanceRequest, serverMetrics); final TimerContext timerContext = queryRequest.getTimerContext(); timerContext.setQueryArrivalTimeNs(queryStartTimeNs); TimerContext.Timer deserializationTimer = timerContext .startNewPhaseTimerAtNs(ServerQueryPhase.REQUEST_DESERIALIZATION, queryStartTimeNs); deserializationTimer.stopAndRecord(); LOGGER.debug("Processing requestId:{},request={}", instanceRequest.getRequestId(), instanceRequest); ListenableFuture<DataTable> queryTask = queryScheduler.submit(queryRequest); // following future will provide default response in case of uncaught // exceptions from query processing ListenableFuture<DataTable> queryResponse = Futures.catching(queryTask, Throwable.class, new Function<Throwable, DataTable>() { @Nullable @Override public DataTable apply(@Nullable Throwable input) { // this is called iff queryTask fails with unhandled exception serverMetrics.addMeteredGlobalValue(ServerMeter.UNCAUGHT_EXCEPTIONS, 1); DataTable result = new DataTableImplV2(); result.addException(QueryException.INTERNAL_ERROR); return result; } }); // transform the DataTable to serialized byte[] to send back to broker ListenableFuture<byte[]> serializedQueryResponse = Futures.transform(queryResponse, new Function<DataTable, byte[]>() { @Nullable @Override public byte[] apply(@Nullable DataTable instanceResponse) { byte[] responseData = serializeDataTable(queryRequest, instanceResponse); LOGGER.info( "Processed requestId {},reqSegments={},prunedToSegmentCount={},deserTimeMs={},planTimeMs={},planExecTimeMs={},totalExecMs={},serTimeMs={}TotalTimeMs={},broker={}", queryRequest.getInstanceRequest().getRequestId(), queryRequest.getInstanceRequest().getSearchSegments().size(), queryRequest.getSegmentCountAfterPruning(), timerContext.getPhaseDurationMs(ServerQueryPhase.REQUEST_DESERIALIZATION), timerContext.getPhaseDurationMs(ServerQueryPhase.BUILD_QUERY_PLAN), timerContext.getPhaseDurationMs(ServerQueryPhase.QUERY_PLAN_EXECUTION), timerContext.getPhaseDurationMs(ServerQueryPhase.QUERY_PROCESSING), timerContext.getPhaseDurationMs(ServerQueryPhase.RESPONSE_SERIALIZATION), timerContext.getPhaseDurationMs(ServerQueryPhase.TOTAL_QUERY_TIME), queryRequest.getBrokerId()); return responseData; } }); return serializedQueryResponse; } static byte[] serializeDataTable(QueryRequest queryRequest, DataTable instanceResponse) { byte[] responseByte; InstanceRequest instanceRequest = queryRequest.getInstanceRequest(); ServerMetrics metrics = queryRequest.getServerMetrics(); TimerContext timerContext = queryRequest.getTimerContext(); timerContext.startNewPhaseTimer(ServerQueryPhase.RESPONSE_SERIALIZATION); long requestId = instanceRequest != null ? instanceRequest.getRequestId() : -1; String brokerId = instanceRequest != null ? instanceRequest.getBrokerId() : "null"; try { if (instanceResponse == null) { LOGGER.warn("Instance response is null for requestId: {}, brokerId: {}", requestId, brokerId); responseByte = new byte[0]; } else { responseByte = instanceResponse.toBytes(); } } catch (Exception e) { metrics.addMeteredGlobalValue(ServerMeter.RESPONSE_SERIALIZATION_EXCEPTIONS, 1); LOGGER.error("Got exception while serializing response for requestId: {}, brokerId: {}", requestId, brokerId, e); responseByte = null; } timerContext.getPhaseTimer(ServerQueryPhase.RESPONSE_SERIALIZATION).stopAndRecord(); timerContext.startNewPhaseTimerAtNs(ServerQueryPhase.TOTAL_QUERY_TIME, timerContext.getQueryArrivalTimeNs()); timerContext.getPhaseTimer(ServerQueryPhase.TOTAL_QUERY_TIME).stopAndRecord(); return responseByte; } }