jiajunwang commented on a change in pull request #827: Add intermediate storage for customized state URL: https://github.com/apache/helix/pull/827#discussion_r386745840
########## File path: helix-core/src/main/java/org/apache/helix/common/caches/ParticipantStateCache.java ########## @@ -0,0 +1,203 @@ +package org.apache.helix.common.caches; + +/* + * 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. + */ + +import com.google.common.collect.Maps; +import java.util.ArrayList; +import java.util.Collections; +import java.util.HashMap; +import java.util.HashSet; +import java.util.List; +import java.util.Map; +import java.util.Set; +import org.apache.helix.HelixDataAccessor; +import org.apache.helix.PropertyKey; +import org.apache.helix.common.controllers.ControlContextProvider; +import org.apache.helix.controller.LogUtil; +import org.apache.helix.model.LiveInstance; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + + +public abstract class ParticipantStateCache<T> extends AbstractDataCache { + private static Logger LOG = LoggerFactory.getLogger(ParticipantStateCache.class.getName()); + protected Map<String, Map<String, Map<String, T>>> _participantStateMap; + + protected Map<PropertyKey, T> _participantStateCache = Maps.newHashMap(); + public ParticipantStateCache(ControlContextProvider controlContextProvider) { + super(controlContextProvider); + _participantStateMap = Collections.emptyMap(); + } + + public ParticipantStateCache(String clusterName) { + this(createDefaultControlContextProvider(clusterName)); + } + + + /** + * This refreshes the participant state cache data by re-fetching the data from zookeeper in an efficient way + * + * @param accessor + * @param liveInstanceMap map of all liveInstances in cluster + * + * @return + */ + public boolean refresh(HelixDataAccessor accessor, + Map<String, LiveInstance> liveInstanceMap, Boolean snapshotEnabled, Set<String> restrictedKeys) { + long startTime = System.currentTimeMillis(); + + refreshParticipantStatesCacheFromZk(accessor, liveInstanceMap, snapshotEnabled, restrictedKeys); + Map<String, Map<String, Map<String, T>>> allParticipantStateMap = new HashMap<>(); + for (PropertyKey key : _participantStateCache.keySet()) { + T participantState = _participantStateCache.get(key); + String[] params = key.getParams(); + if (participantState != null && params.length >= 4) { + String keyLevel1 = params[1]; + String keyLevel2 = params[2]; + String keyLevel3 = params[3]; + Map<String, Map<String, T>> stateMapLevel1 = + allParticipantStateMap.get(keyLevel1); + if (stateMapLevel1 == null) { + stateMapLevel1 = Maps.newHashMap(); + allParticipantStateMap.put(keyLevel1, stateMapLevel1); + } + Map<String, T> stateMapLevel2 = stateMapLevel1.get(keyLevel2); + if (stateMapLevel2 == null) { + stateMapLevel2 = Maps.newHashMap(); + stateMapLevel1.put(keyLevel2, stateMapLevel2); + } + stateMapLevel2.put(keyLevel3, participantState); + } + } + + for (String instance : allParticipantStateMap.keySet()) { + allParticipantStateMap.put(instance, Collections.unmodifiableMap(allParticipantStateMap.get(instance))); + } + _participantStateMap = Collections.unmodifiableMap(allParticipantStateMap); + + long endTime = System.currentTimeMillis(); + LogUtil.logInfo(LOG, genEventInfo(), + "END: participantStateCache.refresh() for cluster " + _controlContextProvider.getClusterName() + + ", started at : " + startTime + ", took " + (endTime - startTime) + " ms"); + if (LOG.isDebugEnabled()) { + LogUtil.logDebug(LOG, genEventInfo(), + String.format("Participant State refreshed : %s", _participantStateMap.toString())); + } + return true; + } + + // reload participant states that has been changed from zk to local cache. + + private void refreshParticipantStatesCacheFromZk(HelixDataAccessor accessor, + Map<String, LiveInstance> liveInstanceMap, Boolean snapshotEnabled, + Set<String> restrictedKeys) { + + long start = System.currentTimeMillis(); + PropertyKey.Builder keyBuilder = accessor.keyBuilder(); + + Set<PropertyKey> participantStateKeys = new HashSet<>(); + for (String instanceName : liveInstanceMap.keySet()) { + LiveInstance liveInstance = liveInstanceMap.get(instanceName); + + if (restrictedKeys.isEmpty()) { + String sessionId = liveInstance.getEphemeralOwner(); + List<String> currentStateNames = + accessor.getChildNames(keyBuilder.currentStates(instanceName, sessionId)); + + for (String currentStateName : currentStateNames) { + participantStateKeys + .add(keyBuilder.currentState(instanceName, sessionId, currentStateName)); + } + } else { + List<String> resourceNames = new ArrayList<>(); + for (String customizedStateType : restrictedKeys) { + resourceNames = accessor + .getChildNames(keyBuilder.customizedStates(instanceName, customizedStateType)); + for (String resourceName : resourceNames) { + participantStateKeys + .add(keyBuilder.customizedState(instanceName, customizedStateType, resourceName)); + } + } + } + } + // All new entries from zk not cached locally yet should be read from ZK. + Set<PropertyKey> reloadKeys = new HashSet<>(participantStateKeys); + reloadKeys.removeAll(_participantStateCache.keySet()); + + Set<PropertyKey> cachedKeys = new HashSet<>(_participantStateCache.keySet()); + cachedKeys.retainAll(participantStateKeys); + + Set<PropertyKey> reloadedKeys = new HashSet<>(); + Map<PropertyKey, T> newStateCache = Collections.unmodifiableMap(refreshProperties(accessor, + reloadKeys, new ArrayList<>(cachedKeys), _participantStateCache, reloadedKeys)); + + if (snapshotEnabled) { + refreshSnapshot(newStateCache, _participantStateCache, reloadedKeys); + } + + _participantStateCache = newStateCache; + + if (LOG.isDebugEnabled()) { + LogUtil.logDebug(LOG, genEventInfo(), "# of participant state reload: " + reloadKeys.size() + + ", skipped:" + (participantStateKeys.size() - reloadKeys.size()) + ". took " + + (System.currentTimeMillis() - start) + " ms to reload new participant states for cluster: " + + _controlContextProvider.getClusterName() + "and state: " + this.getClass().getName()); + } + } + + protected void refreshSnapshot(Map<PropertyKey, T> newStateCache, + Map<PropertyKey, T> participantStateCache, Set<PropertyKey> reloadedKeys) { + } + + /** + * Return the whole participant state map. + * @return + */ + public Map<String, Map<String, Map<String, T>>> getParticipantStatesMap() { + return Collections.unmodifiableMap(_participantStateMap); + } + + /** + * Return all participant states for a certain level1 key. + * @param keyLevel1 + * @return + */ + public Map<String, Map<String, T>> getParticipantStates(String keyLevel1) { + if (!_participantStateMap.containsKey(keyLevel1)) { + return Collections.emptyMap(); + } + return Collections.unmodifiableMap(_participantStateMap.get(keyLevel1)); + } + + /** + * Provides the participant state map for a certain level1 key and level2 key + * @param keyLevel1 + * @param keyLevel2 + * @return + */ + public Map<String, T> getParticipantState(String keyLevel1, Review comment: Optional, both getParticipantStates() methods could be protected and let the children class wrap them and implement with more meaningful public methods. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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