jugomezv commented on code in PR #9994: URL: https://github.com/apache/pinot/pull/9994#discussion_r1065220139
########## pinot-core/src/main/java/org/apache/pinot/core/data/manager/realtime/IngestionDelayTracker.java: ########## @@ -0,0 +1,371 @@ +/** + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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 org.apache.pinot.core.data.manager.realtime; + +import com.google.common.annotations.VisibleForTesting; +import java.time.Clock; +import java.util.ArrayList; +import java.util.HashSet; +import java.util.List; +import java.util.Timer; +import java.util.TimerTask; +import java.util.concurrent.ConcurrentHashMap; +import org.apache.pinot.common.metrics.ServerGauge; +import org.apache.pinot.common.metrics.ServerMetrics; +import org.apache.pinot.spi.utils.builder.TableNameBuilder; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + + +/** + * A Class to track realtime ingestion delay for a given table on a given server. + * Highlights: + * 1-An object of this class is hosted by each RealtimeTableDataManager. + * 2-The object tracks ingestion delays for all partitions hosted by the current server for the given Realtime table. + * 3-Partition delays are updated by all LLRealtimeSegmentDataManager objects hosted in the corresponding + * RealtimeTableDataManager. + * 4-A Metric is derived from reading the maximum tracked by this class. In addition, individual metrics are associated + * with each partition being tracked. + * 5-Delays reported for partitions that do not have events to consume are reported as zero. + * 6-We track the time at which each delay sample was collected so that delay can be increased when partition stops + * consuming for any reason other than no events being available for consumption. + * 7-Partitions whose Segments go from CONSUMING to DROPPED state stop being tracked so their delays do not cloud + * delays of active partitions. + * 8-When a segment goes from CONSUMING to ONLINE, we start a timeout for the corresponding partition. + * If no consumption is noticed after the timeout, we then read ideal state to confirm the server still hosts the + * partition. If not, we stop tracking the respective partition. + * 9-A timer thread is started by this object to track timeouts of partitions and drive the reading of their ideal + * state. + * + * The following diagram illustrates the object interactions with main external APIs + * + * (CONSUMING -> ONLINE state change) + * | + * markPartitionForConfirmation(partitionId) + * | |<-updateIngestionDelay()-{LLRealtimeSegmentDataManager(Partition 0}} + * | | + * ___________V_________________________V_ + * | (Table X) |<-updateIngestionDelay()-{LLRealtimeSegmentDataManager(Partition 1}} + * | IngestionDelayTracker | ... + * |____________________________________|<-updateIngestionDelay()-{LLRealtimeSegmentDataManager (Partition n}} + * ^ ^ + * | \ + * timeoutInactivePartitions() stopTrackingPartitionIngestionDelay(partitionId) + * _________|__________ \ + * | TimerTrackingTask | (CONSUMING -> DROPPED state change) + * |___________________| + * + */ + +public class IngestionDelayTracker { + + // Sleep interval for timer thread that triggers read of ideal state + private static final int TIMER_THREAD_TICK_INTERVAL_MS = 300000; // 5 minutes +/- precision in timeouts + // Once a partition is marked for verification, we wait 10 minutes to pull its ideal state. + private static final int PARTITION_TIMEOUT_MS = 600000; // 10 minutes timeouts + // Delay Timer thread for this amount of time after starting timer + private static final int INITIAL_TIMER_THREAD_DELAY_MS = 100; + + /* + * Class to keep an ingestion delay measure and the time when the sample was taken (i.e. sample time) + * We will use the sample time to increase ingestion delay when a partition stops consuming: the time + * difference between the sample time and current time will be added to the metric when read. + */ + static private class DelayMeasure { + public DelayMeasure(long t, long d) { + _delayMilliseconds = d; + _sampleTime = t; + } + public final long _delayMilliseconds; + public final long _sampleTime; + } + + // HashMap used to store delay measures for all partitions active for the current table. + private final ConcurrentHashMap<Integer, DelayMeasure> _partitionToDelaySampleMap = new ConcurrentHashMap<>(); + // We mark partitions that go from CONSUMING to ONLINE in _partitionsMarkedForVerification: if they do not + // go back to CONSUMING in some period of time, we confirm whether they are still hosted in this server by reading + // ideal state. This is done with the goal of minimizing reading ideal state for efficiency reasons. + private final ConcurrentHashMap<Integer, Long> _partitionsMarkedForVerification = new ConcurrentHashMap<>(); + + final int _timerThreadTickIntervalMs; + // Timer task to check partitions that are inactive against ideal state. + private final Timer _timer; + + private final ServerMetrics _serverMetrics; + private final String _tableNameWithType; + private final String _metricName; + + private final boolean _enablePerPartitionMetric; + private final boolean _enableAggregateMetric; + private final Logger _logger; + + private final RealtimeTableDataManager _realTimeTableDataManager; + private Clock _clock; + + /* + * Returns the maximum ingestion delay amongs all partitions we are tracking. + */ + private DelayMeasure getMaximumDelay() { + DelayMeasure newMax = null; + for (int partitionGroupId : _partitionToDelaySampleMap.keySet()) { + DelayMeasure currentMeasure = _partitionToDelaySampleMap.get(partitionGroupId); + if ((newMax == null) + || + (currentMeasure != null) && (currentMeasure._delayMilliseconds > newMax._delayMilliseconds)) { + newMax = currentMeasure; + } + } + return newMax; + } + + /* + * Helper function to age a delay measure. Aging means adding the time elapsed since the measure was + * taken till the measure is being reported. + * + * @param currentDelay original sample delay to which we will add the age of the measure. + */ + private long getAgedDelay(DelayMeasure currentDelay) { + if (currentDelay == null) { + return 0; // return 0 when not initialized + } + // Add age of measure to the reported value + long measureAgeInMs = _clock.millis() - currentDelay._sampleTime; + // Correct to zero for any time shifts due to NTP or time reset. + measureAgeInMs = Math.max(measureAgeInMs, 0); + return currentDelay._delayMilliseconds + measureAgeInMs; + } + + /* + * Helper function to be called when we should stop tracking a given partition. Removes the partition from + * all our maps. + * + * @param partitionGroupId partition ID which we should stop tracking. + */ + private void removePartitionId(int partitionGroupId) { + _partitionToDelaySampleMap.remove(partitionGroupId); + // If we are removing a partition we should stop reading its ideal state. + _partitionsMarkedForVerification.remove(partitionGroupId); + if (_enablePerPartitionMetric) { + _serverMetrics.removeTableGauge(getPerPartitionMetricName(partitionGroupId), + ServerGauge.TABLE_INGESTION_DELAY_MS); + } + } + + /* + * Helper function to generate a per partition metric name. + * + * @param partitionGroupId the partition group id to be appended to the table name so we + * can differentiate between metrics for various partitions. + * + * @return a metric name with the following structure: _metricName + partitionGroupId + */ + private String getPerPartitionMetricName(int partitionGroupId) { + return _metricName + partitionGroupId; + } + + /* + * Helper functions that creates a list of all the partitions that are marked for verification and whose + * timeouts are expired. This helps us optimize checks of the ideal state. + */ + private ArrayList<Integer> getPartitionsToBeVerified() { + ArrayList<Integer> partitionsToVerify = new ArrayList<>(); + for (int partitionGroupId : _partitionsMarkedForVerification.keySet()) { + long markTime = _partitionsMarkedForVerification.get(partitionGroupId); + long timeMarked = _clock.millis() - markTime; + if (timeMarked > PARTITION_TIMEOUT_MS) { + // Partition must be verified + partitionsToVerify.add(partitionGroupId); + } + } + return partitionsToVerify; + } + + // Custom Constructor + public IngestionDelayTracker(ServerMetrics serverMetrics, String tableNameWithType, + RealtimeTableDataManager realtimeTableDataManager, int timerThreadTickIntervalMs, String metricNamePrefix, + boolean enableAggregateMetric, boolean enablePerPartitionMetric) + throws RuntimeException { + _logger = LoggerFactory.getLogger(getClass().getSimpleName()); + _serverMetrics = serverMetrics; + _tableNameWithType = tableNameWithType; + _metricName = metricNamePrefix + tableNameWithType; Review Comment: significantly simplified all this, see 3ce7b783c5dc88073106f400f00783ba4ab71281 -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: commits-unsubscr...@pinot.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@pinot.apache.org For additional commands, e-mail: commits-h...@pinot.apache.org
