YARN-4219. New levelDB cache storage for timeline v1.5. Contributed by

Li Lu

(cherry picked from commit 9fab22b36673e7f1a0bb629d2c07966ac2482e99)

hadoop-yarn-project/CHANGES.txt

@@ -326,6 +326,8 @@ Release 2.8.0 - UNRELEASED
     YARN-4265. Provide new timeline plugin storage to support fine-grained entity
     caching. (Li Lu and Jason Lowe via junping_du)
 
+    YARN-4219. New levelDB cache storage for timeline v1.5. (Li Lu via xgong)
+
   IMPROVEMENTS
 
     YARN-644. Basic null check is not performed on passed in arguments before

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java

@@ -1702,6 +1702,13 @@ public class YarnConfiguration extends Configuration {
       DEFAULT_TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_RETRY_POLICY_SPEC =
       "2000, 500";
 
+  public static final String TIMELINE_SERVICE_LEVELDB_CACHE_READ_CACHE_SIZE =
+      TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_PREFIX
+          + "leveldb-cache-read-cache-size";
+
+  public static final long
+      DEFAULT_TIMELINE_SERVICE_LEVELDB_CACHE_READ_CACHE_SIZE = 10 * 1024 * 1024;
+
   public static final String TIMELINE_SERVICE_CLIENT_FD_FLUSH_INTERVAL_SECS =
       TIMELINE_SERVICE_CLIENT_PREFIX + "fd-flush-interval-secs";
   public static final long

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml

@@ -2036,6 +2036,14 @@
     <value>604800</value>
   </property>
 
+  <property>
+    <name>yarn.timeline-service.entity-group-fs-store.leveldb-cache-read-cache-size</name>
+    <description>
+      Read cache size for the leveldb cache storage in ATS v1.5 plugin storage.
+    </description>
+    <value>10485760</value>
+  </property>
+
   <!--  Shared Cache Configuration -->
 
   <property>

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-applicationhistoryservice/src/main/java/org/apache/hadoop/yarn/server/timeline/KeyValueBasedTimelineStore.java

@@ -0,0 +1,574 @@
+/**
+ * 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.hadoop.yarn.server.timeline;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.classification.InterfaceAudience.Private;
+import org.apache.hadoop.classification.InterfaceStability.Unstable;
+import org.apache.hadoop.service.AbstractService;
+import org.apache.hadoop.yarn.api.records.timeline.TimelineDomain;
+import org.apache.hadoop.yarn.api.records.timeline.TimelineDomains;
+import org.apache.hadoop.yarn.api.records.timeline.TimelineEntities;
+import org.apache.hadoop.yarn.api.records.timeline.TimelineEntity;
+import org.apache.hadoop.yarn.api.records.timeline.TimelineEvent;
+import org.apache.hadoop.yarn.api.records.timeline.TimelineEvents;
+import org.apache.hadoop.yarn.api.records.timeline.TimelineEvents.EventsOfOneEntity;
+import org.apache.hadoop.yarn.api.records.timeline.TimelinePutResponse;
+import org.apache.hadoop.yarn.api.records.timeline.TimelinePutResponse.TimelinePutError;
+import org.apache.hadoop.yarn.server.timeline.TimelineDataManager.CheckAcl;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.EnumSet;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+import java.util.SortedSet;
+
+import static org.apache.hadoop.yarn.server.timeline.TimelineDataManager.DEFAULT_DOMAIN_ID;
+
+/**
+ * Map based implementation of {@link TimelineStore}. A hash map
+ * implementation should be connected to this implementation through a
+ * {@link TimelineStoreMapAdapter}.
+ *
+ * The methods are synchronized to avoid concurrent modifications.
+ *
+ */
+@Private
+@Unstable
+abstract class KeyValueBasedTimelineStore
+    extends AbstractService implements TimelineStore {
+
+  protected TimelineStoreMapAdapter<EntityIdentifier, TimelineEntity> entities;
+  protected TimelineStoreMapAdapter<EntityIdentifier, Long> entityInsertTimes;
+  protected TimelineStoreMapAdapter<String, TimelineDomain> domainById;
+  protected TimelineStoreMapAdapter<String, Set<TimelineDomain>> domainsByOwner;
+
+  private boolean serviceStopped = false;
+
+  private static final Log LOG
+      = LogFactory.getLog(KeyValueBasedTimelineStore.class);
+
+  public KeyValueBasedTimelineStore() {
+    super(KeyValueBasedTimelineStore.class.getName());
+  }
+
+  public KeyValueBasedTimelineStore(String name) {
+    super(name);
+  }
+
+  public synchronized boolean getServiceStopped() {
+    return serviceStopped;
+  }
+
+  @Override
+  protected synchronized void serviceStop() throws Exception {
+    serviceStopped = true;
+    super.serviceStop();
+  }
+
+  @Override
+  public synchronized TimelineEntities getEntities(String entityType, Long limit,
+      Long windowStart, Long windowEnd, String fromId, Long fromTs,
+      NameValuePair primaryFilter, Collection<NameValuePair> secondaryFilters,
+      EnumSet<Field> fields, CheckAcl checkAcl) throws IOException {
+    if (getServiceStopped()) {
+      LOG.info("Service stopped, return null for the storage");
+      return null;
+    }
+    if (limit == null) {
+      limit = DEFAULT_LIMIT;
+    }
+    if (windowStart == null) {
+      windowStart = Long.MIN_VALUE;
+    }
+    if (windowEnd == null) {
+      windowEnd = Long.MAX_VALUE;
+    }
+    if (fields == null) {
+      fields = EnumSet.allOf(Field.class);
+    }
+
+    Iterator<TimelineEntity> entityIterator = null;
+    if (fromId != null) {
+      TimelineEntity firstEntity = entities.get(new EntityIdentifier(fromId,
+          entityType));
+      if (firstEntity == null) {
+        return new TimelineEntities();
+      } else {
+        entityIterator = entities.valueSetIterator(firstEntity);
+      }
+    }
+    if (entityIterator == null) {
+      entityIterator = entities.valueSetIterator();
+    }
+
+    List<TimelineEntity> entitiesSelected = new ArrayList<TimelineEntity>();
+    while (entityIterator.hasNext()) {
+      TimelineEntity entity = entityIterator.next();
+      if (entitiesSelected.size() >= limit) {
+        break;
+      }
+      if (!entity.getEntityType().equals(entityType)) {
+        continue;
+      }
+      if (entity.getStartTime() <= windowStart) {
+        continue;
+      }
+      if (entity.getStartTime() > windowEnd) {
+        continue;
+      }
+      if (fromTs != null && entityInsertTimes.get(new EntityIdentifier(
+          entity.getEntityId(), entity.getEntityType())) > fromTs) {
+        continue;
+      }
+      if (primaryFilter != null &&
+          !KeyValueBasedTimelineStoreUtils.matchPrimaryFilter(
+              entity.getPrimaryFilters(), primaryFilter)) {
+        continue;
+      }
+      if (secondaryFilters != null) { // AND logic
+        boolean flag = true;
+        for (NameValuePair secondaryFilter : secondaryFilters) {
+          if (secondaryFilter != null && !KeyValueBasedTimelineStoreUtils
+              .matchPrimaryFilter(entity.getPrimaryFilters(), secondaryFilter)
+              && !KeyValueBasedTimelineStoreUtils.matchFilter(
+              entity.getOtherInfo(), secondaryFilter)) {
+            flag = false;
+            break;
+          }
+        }
+        if (!flag) {
+          continue;
+        }
+      }
+      if (entity.getDomainId() == null) {
+        entity.setDomainId(DEFAULT_DOMAIN_ID);
+      }
+      if (checkAcl == null || checkAcl.check(entity)) {
+        entitiesSelected.add(entity);
+      }
+    }
+    List<TimelineEntity> entitiesToReturn = new ArrayList<TimelineEntity>();
+    for (TimelineEntity entitySelected : entitiesSelected) {
+      entitiesToReturn.add(KeyValueBasedTimelineStoreUtils.maskFields(
+          entitySelected, fields));
+    }
+    Collections.sort(entitiesToReturn);
+    TimelineEntities entitiesWrapper = new TimelineEntities();
+    entitiesWrapper.setEntities(entitiesToReturn);
+    return entitiesWrapper;
+  }
+
+  @Override
+  public synchronized TimelineEntity getEntity(String entityId, String entityType,
+      EnumSet<Field> fieldsToRetrieve) {
+    if (getServiceStopped()) {
+      LOG.info("Service stopped, return null for the storage");
+      return null;
+    }
+    if (fieldsToRetrieve == null) {
+      fieldsToRetrieve = EnumSet.allOf(Field.class);
+    }
+    TimelineEntity
+        entity = entities.get(new EntityIdentifier(entityId, entityType));
+    if (entity == null) {
+      return null;
+    } else {
+      return KeyValueBasedTimelineStoreUtils.maskFields(
+          entity, fieldsToRetrieve);
+    }
+  }
+
+  @Override
+  public synchronized TimelineEvents getEntityTimelines(String entityType,
+      SortedSet<String> entityIds, Long limit, Long windowStart,
+      Long windowEnd,
+      Set<String> eventTypes) {
+    if (getServiceStopped()) {
+      LOG.info("Service stopped, return null for the storage");
+      return null;
+    }
+    TimelineEvents allEvents = new TimelineEvents();
+    if (entityIds == null) {
+      return allEvents;
+    }
+    if (limit == null) {
+      limit = DEFAULT_LIMIT;
+    }
+    if (windowStart == null) {
+      windowStart = Long.MIN_VALUE;
+    }
+    if (windowEnd == null) {
+      windowEnd = Long.MAX_VALUE;
+    }
+    for (String entityId : entityIds) {
+      EntityIdentifier entityID = new EntityIdentifier(entityId, entityType);
+      TimelineEntity entity = entities.get(entityID);
+      if (entity == null) {
+        continue;
+      }
+      EventsOfOneEntity events = new EventsOfOneEntity();
+      events.setEntityId(entityId);
+      events.setEntityType(entityType);
+      for (TimelineEvent event : entity.getEvents()) {
+        if (events.getEvents().size() >= limit) {
+          break;
+        }
+        if (event.getTimestamp() <= windowStart) {
+          continue;
+        }
+        if (event.getTimestamp() > windowEnd) {
+          continue;
+        }
+        if (eventTypes != null && !eventTypes.contains(event.getEventType())) {
+          continue;
+        }
+        events.addEvent(event);
+      }
+      allEvents.addEvent(events);
+    }
+    return allEvents;
+  }
+
+  @Override
+  public TimelineDomain getDomain(String domainId)
+      throws IOException {
+    if (getServiceStopped()) {
+      LOG.info("Service stopped, return null for the storage");
+      return null;
+    }
+    TimelineDomain domain = domainById.get(domainId);
+    if (domain == null) {
+      return null;
+    } else {
+      return KeyValueBasedTimelineStoreUtils.createTimelineDomain(
+          domain.getId(),
+          domain.getDescription(),
+          domain.getOwner(),
+          domain.getReaders(),
+          domain.getWriters(),
+          domain.getCreatedTime(),
+          domain.getModifiedTime());
+    }
+  }
+
+  @Override
+  public TimelineDomains getDomains(String owner)
+      throws IOException {
+    if (getServiceStopped()) {
+      LOG.info("Service stopped, return null for the storage");
+      return null;
+    }
+    List<TimelineDomain> domains = new ArrayList<TimelineDomain>();
+    Set<TimelineDomain> domainsOfOneOwner = domainsByOwner.get(owner);
+    if (domainsOfOneOwner == null) {
+      return new TimelineDomains();
+    }
+    for (TimelineDomain domain : domainsByOwner.get(owner)) {
+      TimelineDomain domainToReturn = KeyValueBasedTimelineStoreUtils
+          .createTimelineDomain(
+              domain.getId(),
+              domain.getDescription(),
+              domain.getOwner(),
+              domain.getReaders(),
+              domain.getWriters(),
+              domain.getCreatedTime(),
+              domain.getModifiedTime());
+      domains.add(domainToReturn);
+    }
+    Collections.sort(domains, new Comparator<TimelineDomain>() {
+      @Override
+      public int compare(
+          TimelineDomain domain1, TimelineDomain domain2) {
+         int result = domain2.getCreatedTime().compareTo(
+             domain1.getCreatedTime());
+         if (result == 0) {
+           return domain2.getModifiedTime().compareTo(
+               domain1.getModifiedTime());
+         } else {
+           return result;
+         }
+      }
+    });
+    TimelineDomains domainsToReturn = new TimelineDomains();
+    domainsToReturn.addDomains(domains);
+    return domainsToReturn;
+  }
+
+  @Override
+  public synchronized TimelinePutResponse put(TimelineEntities data) {
+    TimelinePutResponse response = new TimelinePutResponse();
+    if (getServiceStopped()) {
+      LOG.info("Service stopped, return null for the storage");
+      TimelinePutError error = new TimelinePutError();
+      error.setErrorCode(TimelinePutError.IO_EXCEPTION);
+      response.addError(error);
+      return response;
+    }
+    for (TimelineEntity entity : data.getEntities()) {
+      EntityIdentifier entityId =
+          new EntityIdentifier(entity.getEntityId(), entity.getEntityType());
+      // store entity info in memory
+      TimelineEntity existingEntity = entities.get(entityId);
+      boolean needsPut = false;
+      if (existingEntity == null) {
+        existingEntity = new TimelineEntity();
+        existingEntity.setEntityId(entity.getEntityId());
+        existingEntity.setEntityType(entity.getEntityType());
+        existingEntity.setStartTime(entity.getStartTime());
+        if (entity.getDomainId() == null ||
+            entity.getDomainId().length() == 0) {
+          TimelinePutError error = new TimelinePutError();
+          error.setEntityId(entityId.getId());
+          error.setEntityType(entityId.getType());
+          error.setErrorCode(TimelinePutError.NO_DOMAIN);
+          response.addError(error);
+          continue;
+        }
+        existingEntity.setDomainId(entity.getDomainId());
+        // insert a new entity to the storage, update insert time map
+        entityInsertTimes.put(entityId, System.currentTimeMillis());
+        needsPut = true;
+      }
+      if (entity.getEvents() != null) {
+        if (existingEntity.getEvents() == null) {
+          existingEntity.setEvents(entity.getEvents());
+        } else {
+          existingEntity.addEvents(entity.getEvents());
+        }
+        Collections.sort(existingEntity.getEvents());
+        needsPut = true;
+      }
+      // check startTime
+      if (existingEntity.getStartTime() == null) {
+        if (existingEntity.getEvents() == null
+            || existingEntity.getEvents().isEmpty()) {
+          TimelinePutError error = new TimelinePutError();
+          error.setEntityId(entityId.getId());
+          error.setEntityType(entityId.getType());
+          error.setErrorCode(TimelinePutError.NO_START_TIME);
+          response.addError(error);
+          entities.remove(entityId);
+          entityInsertTimes.remove(entityId);
+          continue;
+        } else {
+          Long min = Long.MAX_VALUE;
+          for (TimelineEvent e : entity.getEvents()) {
+            if (min > e.getTimestamp()) {
+              min = e.getTimestamp();
+            }
+          }
+          existingEntity.setStartTime(min);
+          needsPut = true;
+        }
+      }
+      if (entity.getPrimaryFilters() != null) {
+        if (existingEntity.getPrimaryFilters() == null) {
+          existingEntity.setPrimaryFilters(new HashMap<String, Set<Object>>());
+        }
+        for (Entry<String, Set<Object>> pf :
+            entity.getPrimaryFilters().entrySet()) {
+          for (Object pfo : pf.getValue()) {
+            existingEntity.addPrimaryFilter(pf.getKey(),
+                KeyValueBasedTimelineStoreUtils.compactNumber(pfo));
+            needsPut = true;
+          }
+        }
+      }
+      if (entity.getOtherInfo() != null) {
+        if (existingEntity.getOtherInfo() == null) {
+          existingEntity.setOtherInfo(new HashMap<String, Object>());
+        }
+        for (Entry<String, Object> info : entity.getOtherInfo().entrySet()) {
+          existingEntity.addOtherInfo(info.getKey(),
+              KeyValueBasedTimelineStoreUtils.compactNumber(info.getValue()));
+          needsPut = true;
+        }
+      }
+      if (needsPut) {
+        entities.put(entityId, existingEntity);
+      }
+
+      // relate it to other entities
+      if (entity.getRelatedEntities() == null) {
+        continue;
+      }
+      for (Entry<String, Set<String>> partRelatedEntities : entity
+          .getRelatedEntities().entrySet()) {
+        if (partRelatedEntities == null) {
+          continue;
+        }
+        for (String idStr : partRelatedEntities.getValue()) {
+          EntityIdentifier relatedEntityId =
+              new EntityIdentifier(idStr, partRelatedEntities.getKey());
+          TimelineEntity relatedEntity = entities.get(relatedEntityId);
+          if (relatedEntity != null) {
+            if (relatedEntity.getDomainId().equals(
+                existingEntity.getDomainId())) {
+              relatedEntity.addRelatedEntity(
+                  existingEntity.getEntityType(), existingEntity.getEntityId());
+              entities.put(relatedEntityId, relatedEntity);
+            } else {
+              // in this case the entity will be put, but the relation will be
+              // ignored
+              TimelinePutError error = new TimelinePutError();
+              error.setEntityType(existingEntity.getEntityType());
+              error.setEntityId(existingEntity.getEntityId());
+              error.setErrorCode(TimelinePutError.FORBIDDEN_RELATION);
+              response.addError(error);
+            }
+          } else {
+            relatedEntity = new TimelineEntity();
+            relatedEntity.setEntityId(relatedEntityId.getId());
+            relatedEntity.setEntityType(relatedEntityId.getType());
+            relatedEntity.setStartTime(existingEntity.getStartTime());
+            relatedEntity.addRelatedEntity(existingEntity.getEntityType(),
+                existingEntity.getEntityId());
+            relatedEntity.setDomainId(existingEntity.getDomainId());
+            entities.put(relatedEntityId, relatedEntity);
+            entityInsertTimes.put(relatedEntityId, System.currentTimeMillis());
+          }
+        }
+      }
+    }
+    return response;
+  }
+
+  public void put(TimelineDomain domain) throws IOException {
+    if (getServiceStopped()) {
+      LOG.info("Service stopped, return null for the storage");
+      return;
+    }
+    TimelineDomain domainToReplace =
+        domainById.get(domain.getId());
+    Long currentTimestamp = System.currentTimeMillis();
+    TimelineDomain domainToStore
+        = KeyValueBasedTimelineStoreUtils.createTimelineDomain(
+        domain.getId(), domain.getDescription(), domain.getOwner(),
+        domain.getReaders(), domain.getWriters(),
+        (domainToReplace == null ?
+            currentTimestamp : domainToReplace.getCreatedTime()),
+        currentTimestamp);
+    domainById.put(domainToStore.getId(), domainToStore);
+    Set<TimelineDomain> domainsByOneOwner =
+        domainsByOwner.get(domainToStore.getOwner());
+    if (domainsByOneOwner == null) {
+      domainsByOneOwner = new HashSet<TimelineDomain>();
+      domainsByOwner.put(domainToStore.getOwner(), domainsByOneOwner);
+    }
+    if (domainToReplace != null) {
+      domainsByOneOwner.remove(domainToReplace);
+    }
+    domainsByOneOwner.add(domainToStore);
+  }
+
+  private static class KeyValueBasedTimelineStoreUtils {
+
+    static TimelineDomain createTimelineDomain(
+        String id, String description, String owner,
+        String readers, String writers,
+        Long createdTime, Long modifiedTime) {
+      TimelineDomain domainToStore = new TimelineDomain();
+      domainToStore.setId(id);
+      domainToStore.setDescription(description);
+      domainToStore.setOwner(owner);
+      domainToStore.setReaders(readers);
+      domainToStore.setWriters(writers);
+      domainToStore.setCreatedTime(createdTime);
+      domainToStore.setModifiedTime(modifiedTime);
+      return domainToStore;
+    }
+
+    static TimelineEntity maskFields(
+        TimelineEntity entity, EnumSet<Field> fields) {
+      // Conceal the fields that are not going to be exposed
+      TimelineEntity entityToReturn = new TimelineEntity();
+      entityToReturn.setEntityId(entity.getEntityId());
+      entityToReturn.setEntityType(entity.getEntityType());
+      entityToReturn.setStartTime(entity.getStartTime());
+      entityToReturn.setDomainId(entity.getDomainId());
+      // Deep copy
+      if (fields.contains(Field.EVENTS)) {
+        entityToReturn.addEvents(entity.getEvents());
+      } else if (fields.contains(Field.LAST_EVENT_ONLY)) {
+        entityToReturn.addEvent(entity.getEvents().get(0));
+      } else {
+        entityToReturn.setEvents(null);
+      }
+      if (fields.contains(Field.RELATED_ENTITIES)) {
+        entityToReturn.addRelatedEntities(entity.getRelatedEntities());
+      } else {
+        entityToReturn.setRelatedEntities(null);
+      }
+      if (fields.contains(Field.PRIMARY_FILTERS)) {
+        entityToReturn.addPrimaryFilters(entity.getPrimaryFilters());
+      } else {
+        entityToReturn.setPrimaryFilters(null);
+      }
+      if (fields.contains(Field.OTHER_INFO)) {
+        entityToReturn.addOtherInfo(entity.getOtherInfo());
+      } else {
+        entityToReturn.setOtherInfo(null);
+      }
+      return entityToReturn;
+    }
+
+    static boolean matchFilter(Map<String, Object> tags,
+        NameValuePair filter) {
+      Object value = tags.get(filter.getName());
+      if (value == null) { // doesn't have the filter
+        return false;
+      } else if (!value.equals(filter.getValue())) { // doesn't match the filter
+        return false;
+      }
+      return true;
+    }
+
+    static boolean matchPrimaryFilter(Map<String, Set<Object>> tags,
+        NameValuePair filter) {
+      Set<Object> value = tags.get(filter.getName());
+      if (value == null) { // doesn't have the filter
+        return false;
+      } else {
+        return value.contains(filter.getValue());
+      }
+    }
+
+    static Object compactNumber(Object o) {
+      if (o instanceof Long) {
+        Long l = (Long) o;
+        if (l >= Integer.MIN_VALUE && l <= Integer.MAX_VALUE) {
+          return l.intValue();
+        }
+      }
+      return o;
+    }
+  }
+
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-applicationhistoryservice/src/main/java/org/apache/hadoop/yarn/server/timeline/MemoryTimelineStore.java

@@ -18,39 +18,14 @@
 
 package org.apache.hadoop.yarn.server.timeline;
 
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.Comparator;
-import java.util.EnumSet;
+import org.apache.hadoop.classification.InterfaceAudience.Private;
+import org.apache.hadoop.classification.InterfaceStability.Unstable;
+
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.Iterator;
-import java.util.List;
 import java.util.Map;
-import java.util.Map.Entry;
-import java.util.PriorityQueue;
-import java.util.Set;
-import java.util.SortedSet;
 import java.util.TreeSet;
 
-import org.apache.hadoop.classification.InterfaceAudience.Private;
-import org.apache.hadoop.classification.InterfaceStability.Unstable;
-import org.apache.hadoop.service.AbstractService;
-import org.apache.hadoop.yarn.api.records.timeline.TimelineEntities;
-import org.apache.hadoop.yarn.api.records.timeline.TimelineEntity;
-import org.apache.hadoop.yarn.api.records.timeline.TimelineEvent;
-import org.apache.hadoop.yarn.api.records.timeline.TimelineEvents;
-import org.apache.hadoop.yarn.api.records.timeline.TimelineEvents.EventsOfOneEntity;
-import org.apache.hadoop.yarn.api.records.timeline.TimelineDomain;
-import org.apache.hadoop.yarn.api.records.timeline.TimelineDomains;
-import org.apache.hadoop.yarn.api.records.timeline.TimelinePutResponse;
-import org.apache.hadoop.yarn.api.records.timeline.TimelinePutResponse.TimelinePutError;
-import org.apache.hadoop.yarn.server.timeline.TimelineDataManager.CheckAcl;
-
-import static org.apache.hadoop.yarn.server.timeline.TimelineDataManager.DEFAULT_DOMAIN_ID;
-
 /**
  * In-memory implementation of {@link TimelineStore}. This
  * implementation is for test purpose only. If users improperly instantiate it,
@@ -62,448 +37,60 @@ import static org.apache.hadoop.yarn.server.timeline.TimelineDataManager.DEFAULT
  */
 @Private
 @Unstable
-public class MemoryTimelineStore
-    extends AbstractService implements TimelineStore {
-
-  private Map<EntityIdentifier, TimelineEntity> entities =
-      new HashMap<EntityIdentifier, TimelineEntity>();
-  private Map<EntityIdentifier, Long> entityInsertTimes =
-      new HashMap<EntityIdentifier, Long>();
-  private Map<String, TimelineDomain> domainsById =
-      new HashMap<String, TimelineDomain>();
-  private Map<String, Set<TimelineDomain>> domainsByOwner =
-      new HashMap<String, Set<TimelineDomain>>();
+public class MemoryTimelineStore extends KeyValueBasedTimelineStore {
 
-  public MemoryTimelineStore() {
-    super(MemoryTimelineStore.class.getName());
-  }
+  static class HashMapStoreAdapter<K, V>
+      implements TimelineStoreMapAdapter<K, V> {
+    Map<K, V> internalMap = new HashMap<>();
 
-  @Override
-  public synchronized TimelineEntities getEntities(String entityType, Long limit,
-      Long windowStart, Long windowEnd, String fromId, Long fromTs,
-      NameValuePair primaryFilter, Collection<NameValuePair> secondaryFilters,
-      EnumSet<Field> fields, CheckAcl checkAcl) throws IOException {
-    if (limit == null) {
-      limit = DEFAULT_LIMIT;
-    }
-    if (windowStart == null) {
-      windowStart = Long.MIN_VALUE;
-    }
-    if (windowEnd == null) {
-      windowEnd = Long.MAX_VALUE;
-    }
-    if (fields == null) {
-      fields = EnumSet.allOf(Field.class);
+    @Override
+    public V get(K key) {
+      return internalMap.get(key);
     }
 
-    Iterator<TimelineEntity> entityIterator = null;
-    if (fromId != null) {
-      TimelineEntity firstEntity = entities.get(new EntityIdentifier(fromId,
-          entityType));
-      if (firstEntity == null) {
-        return new TimelineEntities();
-      } else {
-        entityIterator = new TreeSet<TimelineEntity>(entities.values())
-            .tailSet(firstEntity, true).iterator();
-      }
-    }
-    if (entityIterator == null) {
-      entityIterator = new PriorityQueue<TimelineEntity>(entities.values())
-          .iterator();
+    @Override
+    public void put(K key, V value) {
+      internalMap.put(key, value);
     }
 
-    List<TimelineEntity> entitiesSelected = new ArrayList<TimelineEntity>();
-    while (entityIterator.hasNext()) {
-      TimelineEntity entity = entityIterator.next();
-      if (entitiesSelected.size() >= limit) {
-        break;
-      }
-      if (!entity.getEntityType().equals(entityType)) {
-        continue;
-      }
-      if (entity.getStartTime() <= windowStart) {
-        continue;
-      }
-      if (entity.getStartTime() > windowEnd) {
-        continue;
-      }
-      if (fromTs != null && entityInsertTimes.get(new EntityIdentifier(
-          entity.getEntityId(), entity.getEntityType())) > fromTs) {
-        continue;
-      }
-      if (primaryFilter != null &&
-          !matchPrimaryFilter(entity.getPrimaryFilters(), primaryFilter)) {
-        continue;
-      }
-      if (secondaryFilters != null) { // AND logic
-        boolean flag = true;
-        for (NameValuePair secondaryFilter : secondaryFilters) {
-          if (secondaryFilter != null && !matchPrimaryFilter(
-              entity.getPrimaryFilters(), secondaryFilter) &&
-              !matchFilter(entity.getOtherInfo(), secondaryFilter)) {
-            flag = false;
-            break;
-          }
-        }
-        if (!flag) {
-          continue;
-        }
-      }
-      if (entity.getDomainId() == null) {
-        entity.setDomainId(DEFAULT_DOMAIN_ID);
-      }
-      if (checkAcl == null || checkAcl.check(entity)) {
-        entitiesSelected.add(entity);
-      }
-    }
-    List<TimelineEntity> entitiesToReturn = new ArrayList<TimelineEntity>();
-    for (TimelineEntity entitySelected : entitiesSelected) {
-      entitiesToReturn.add(maskFields(entitySelected, fields));
+    @Override
+    public void remove(K key) {
+      internalMap.remove(key);
     }
-    Collections.sort(entitiesToReturn);
-    TimelineEntities entitiesWrapper = new TimelineEntities();
-    entitiesWrapper.setEntities(entitiesToReturn);
-    return entitiesWrapper;
-  }
-
-  @Override
-  public synchronized TimelineEntity getEntity(String entityId, String entityType,
-      EnumSet<Field> fieldsToRetrieve) {
-    if (fieldsToRetrieve == null) {
-      fieldsToRetrieve = EnumSet.allOf(Field.class);
-    }
-    TimelineEntity entity = entities.get(new EntityIdentifier(entityId, entityType));
-    if (entity == null) {
-      return null;
-    } else {
-      return maskFields(entity, fieldsToRetrieve);
-    }
-  }
 
-  @Override
-  public synchronized TimelineEvents getEntityTimelines(String entityType,
-      SortedSet<String> entityIds, Long limit, Long windowStart,
-      Long windowEnd,
-      Set<String> eventTypes) {
-    TimelineEvents allEvents = new TimelineEvents();
-    if (entityIds == null) {
-      return allEvents;
+    @Override
+    public Iterator<V>
+    valueSetIterator() {
+      return new TreeSet<>(internalMap.values()).iterator();
     }
-    if (limit == null) {
-      limit = DEFAULT_LIMIT;
-    }
-    if (windowStart == null) {
-      windowStart = Long.MIN_VALUE;
-    }
-    if (windowEnd == null) {
-      windowEnd = Long.MAX_VALUE;
-    }
-    for (String entityId : entityIds) {
-      EntityIdentifier entityID = new EntityIdentifier(entityId, entityType);
-      TimelineEntity entity = entities.get(entityID);
-      if (entity == null) {
-        continue;
-      }
-      EventsOfOneEntity events = new EventsOfOneEntity();
-      events.setEntityId(entityId);
-      events.setEntityType(entityType);
-      for (TimelineEvent event : entity.getEvents()) {
-        if (events.getEvents().size() >= limit) {
-          break;
-        }
-        if (event.getTimestamp() <= windowStart) {
-          continue;
-        }
-        if (event.getTimestamp() > windowEnd) {
-          continue;
-        }
-        if (eventTypes != null && !eventTypes.contains(event.getEventType())) {
-          continue;
-        }
-        events.addEvent(event);
-      }
-      allEvents.addEvent(events);
-    }
-    return allEvents;
-  }
 
-  @Override
-  public TimelineDomain getDomain(String domainId)
-      throws IOException {
-    TimelineDomain domain = domainsById.get(domainId);
-    if (domain == null) {
-      return null;
-    } else {
-      return createTimelineDomain(
-          domain.getId(),
-          domain.getDescription(),
-          domain.getOwner(),
-          domain.getReaders(),
-          domain.getWriters(),
-          domain.getCreatedTime(),
-          domain.getModifiedTime());
-    }
-  }
-
-  @Override
-  public TimelineDomains getDomains(String owner)
-      throws IOException {
-    List<TimelineDomain> domains = new ArrayList<TimelineDomain>();
-    Set<TimelineDomain> domainsOfOneOwner = domainsByOwner.get(owner);
-    if (domainsOfOneOwner == null) {
-      return new TimelineDomains();
-    }
-    for (TimelineDomain domain : domainsByOwner.get(owner)) {
-      TimelineDomain domainToReturn = createTimelineDomain(
-          domain.getId(),
-          domain.getDescription(),
-          domain.getOwner(),
-          domain.getReaders(),
-          domain.getWriters(),
-          domain.getCreatedTime(),
-          domain.getModifiedTime());
-      domains.add(domainToReturn);
-    }
-    Collections.sort(domains, new Comparator<TimelineDomain>() {
-      @Override
-      public int compare(
-          TimelineDomain domain1, TimelineDomain domain2) {
-         int result = domain2.getCreatedTime().compareTo(
-             domain1.getCreatedTime());
-         if (result == 0) {
-           return domain2.getModifiedTime().compareTo(
-               domain1.getModifiedTime());
-         } else {
-           return result;
-         }
-      }
-    });
-    TimelineDomains domainsToReturn = new TimelineDomains();
-    domainsToReturn.addDomains(domains);
-    return domainsToReturn;
-  }
-
-  @Override
-  public synchronized TimelinePutResponse put(TimelineEntities data) {
-    TimelinePutResponse response = new TimelinePutResponse();
-    for (TimelineEntity entity : data.getEntities()) {
-      EntityIdentifier entityId =
-          new EntityIdentifier(entity.getEntityId(), entity.getEntityType());
-      // store entity info in memory
-      TimelineEntity existingEntity = entities.get(entityId);
-      if (existingEntity == null) {
-        existingEntity = new TimelineEntity();
-        existingEntity.setEntityId(entity.getEntityId());
-        existingEntity.setEntityType(entity.getEntityType());
-        existingEntity.setStartTime(entity.getStartTime());
-        if (entity.getDomainId() == null ||
-            entity.getDomainId().length() == 0) {
-          TimelinePutError error = new TimelinePutError();
-          error.setEntityId(entityId.getId());
-          error.setEntityType(entityId.getType());
-          error.setErrorCode(TimelinePutError.NO_DOMAIN);
-          response.addError(error);
-          continue;
-        }
-        existingEntity.setDomainId(entity.getDomainId());
-        entities.put(entityId, existingEntity);
-        entityInsertTimes.put(entityId, System.currentTimeMillis());
-      }
-      if (entity.getEvents() != null) {
-        if (existingEntity.getEvents() == null) {
-          existingEntity.setEvents(entity.getEvents());
-        } else {
-          existingEntity.addEvents(entity.getEvents());
-        }
-        Collections.sort(existingEntity.getEvents());
-      }
-      // check startTime
-      if (existingEntity.getStartTime() == null) {
-        if (existingEntity.getEvents() == null
-            || existingEntity.getEvents().isEmpty()) {
-          TimelinePutError error = new TimelinePutError();
-          error.setEntityId(entityId.getId());
-          error.setEntityType(entityId.getType());
-          error.setErrorCode(TimelinePutError.NO_START_TIME);
-          response.addError(error);
-          entities.remove(entityId);
-          entityInsertTimes.remove(entityId);
-          continue;
-        } else {
-          Long min = Long.MAX_VALUE;
-          for (TimelineEvent e : entity.getEvents()) {
-            if (min > e.getTimestamp()) {
-              min = e.getTimestamp();
-            }
-          }
-          existingEntity.setStartTime(min);
-        }
-      }
-      if (entity.getPrimaryFilters() != null) {
-        if (existingEntity.getPrimaryFilters() == null) {
-          existingEntity.setPrimaryFilters(new HashMap<String, Set<Object>>());
-        }
-        for (Entry<String, Set<Object>> pf :
-            entity.getPrimaryFilters().entrySet()) {
-          for (Object pfo : pf.getValue()) {
-            existingEntity.addPrimaryFilter(pf.getKey(), maybeConvert(pfo));
-          }
-        }
-      }
-      if (entity.getOtherInfo() != null) {
-        if (existingEntity.getOtherInfo() == null) {
-          existingEntity.setOtherInfo(new HashMap<String, Object>());
-        }
-        for (Entry<String, Object> info : entity.getOtherInfo().entrySet()) {
-          existingEntity.addOtherInfo(info.getKey(),
-              maybeConvert(info.getValue()));
-        }
-      }
-      // relate it to other entities
-      if (entity.getRelatedEntities() == null) {
-        continue;
-      }
-      for (Map.Entry<String, Set<String>> partRelatedEntities : entity
-          .getRelatedEntities().entrySet()) {
-        if (partRelatedEntities == null) {
-          continue;
-        }
-        for (String idStr : partRelatedEntities.getValue()) {
-          EntityIdentifier relatedEntityId =
-              new EntityIdentifier(idStr, partRelatedEntities.getKey());
-          TimelineEntity relatedEntity = entities.get(relatedEntityId);
-          if (relatedEntity != null) {
-            if (relatedEntity.getDomainId().equals(
-                existingEntity.getDomainId())) {
-              relatedEntity.addRelatedEntity(
-                  existingEntity.getEntityType(), existingEntity.getEntityId());
-            } else {
-              // in this case the entity will be put, but the relation will be
-              // ignored
-              TimelinePutError error = new TimelinePutError();
-              error.setEntityType(existingEntity.getEntityType());
-              error.setEntityId(existingEntity.getEntityId());
-              error.setErrorCode(TimelinePutError.FORBIDDEN_RELATION);
-              response.addError(error);
-            }
-          } else {
-            relatedEntity = new TimelineEntity();
-            relatedEntity.setEntityId(relatedEntityId.getId());
-            relatedEntity.setEntityType(relatedEntityId.getType());
-            relatedEntity.setStartTime(existingEntity.getStartTime());
-            relatedEntity.addRelatedEntity(existingEntity.getEntityType(),
-                existingEntity.getEntityId());
-            relatedEntity.setDomainId(existingEntity.getDomainId());
-            entities.put(relatedEntityId, relatedEntity);
-            entityInsertTimes.put(relatedEntityId, System.currentTimeMillis());
+    @Override
+    @SuppressWarnings("unchecked")
+    public Iterator<V> valueSetIterator(V minV) {
+      if (minV instanceof Comparable) {
+        TreeSet<V> tempTreeSet = new TreeSet<>();
+        for (V value : internalMap.values()) {
+          if (((Comparable) value).compareTo(minV) >= 0) {
+            tempTreeSet.add(value);
           }
         }
+        return tempTreeSet.iterator();
+      } else {
+        return valueSetIterator();
       }
     }
-    return response;
-  }
-
-  public void put(TimelineDomain domain) throws IOException {
-    TimelineDomain domainToReplace =
-        domainsById.get(domain.getId());
-    Long currentTimestamp = System.currentTimeMillis();
-    TimelineDomain domainToStore = createTimelineDomain(
-        domain.getId(), domain.getDescription(), domain.getOwner(),
-        domain.getReaders(), domain.getWriters(),
-        (domainToReplace == null ?
-            currentTimestamp : domainToReplace.getCreatedTime()),
-        currentTimestamp);
-    domainsById.put(domainToStore.getId(), domainToStore);
-    Set<TimelineDomain> domainsByOneOwner =
-        domainsByOwner.get(domainToStore.getOwner());
-    if (domainsByOneOwner == null) {
-      domainsByOneOwner = new HashSet<TimelineDomain>();
-      domainsByOwner.put(domainToStore.getOwner(), domainsByOneOwner);
-    }
-    if (domainToReplace != null) {
-      domainsByOneOwner.remove(domainToReplace);
-    }
-    domainsByOneOwner.add(domainToStore);
-  }
-
-  private static TimelineDomain createTimelineDomain(
-      String id, String description, String owner,
-      String readers, String writers,
-      Long createdTime, Long modifiedTime) {
-    TimelineDomain domainToStore = new TimelineDomain();
-    domainToStore.setId(id);
-    domainToStore.setDescription(description);
-    domainToStore.setOwner(owner);
-    domainToStore.setReaders(readers);
-    domainToStore.setWriters(writers);
-    domainToStore.setCreatedTime(createdTime);
-    domainToStore.setModifiedTime(modifiedTime);
-    return domainToStore;
-  }
-
-  private static TimelineEntity maskFields(
-      TimelineEntity entity, EnumSet<Field> fields) {
-    // Conceal the fields that are not going to be exposed
-    TimelineEntity entityToReturn = new TimelineEntity();
-    entityToReturn.setEntityId(entity.getEntityId());
-    entityToReturn.setEntityType(entity.getEntityType());
-    entityToReturn.setStartTime(entity.getStartTime());
-    entityToReturn.setDomainId(entity.getDomainId());
-    // Deep copy
-    if (fields.contains(Field.EVENTS)) {
-      entityToReturn.addEvents(entity.getEvents());
-    } else if (fields.contains(Field.LAST_EVENT_ONLY)) {
-      entityToReturn.addEvent(entity.getEvents().get(0));
-    } else {
-      entityToReturn.setEvents(null);
-    }
-    if (fields.contains(Field.RELATED_ENTITIES)) {
-      entityToReturn.addRelatedEntities(entity.getRelatedEntities());
-    } else {
-      entityToReturn.setRelatedEntities(null);
-    }
-    if (fields.contains(Field.PRIMARY_FILTERS)) {
-      entityToReturn.addPrimaryFilters(entity.getPrimaryFilters());
-    } else {
-      entityToReturn.setPrimaryFilters(null);
-    }
-    if (fields.contains(Field.OTHER_INFO)) {
-      entityToReturn.addOtherInfo(entity.getOtherInfo());
-    } else {
-      entityToReturn.setOtherInfo(null);
-    }
-    return entityToReturn;
   }
 
-  private static boolean matchFilter(Map<String, Object> tags,
-      NameValuePair filter) {
-    Object value = tags.get(filter.getName());
-    if (value == null) { // doesn't have the filter
-      return false;
-    } else if (!value.equals(filter.getValue())) { // doesn't match the filter
-      return false;
-    }
-    return true;
-  }
-
-  private static boolean matchPrimaryFilter(Map<String, Set<Object>> tags,
-      NameValuePair filter) {
-    Set<Object> value = tags.get(filter.getName());
-    if (value == null) { // doesn't have the filter
-      return false;
-    } else {
-      return value.contains(filter.getValue());
-    }
+  public MemoryTimelineStore() {
+    this(MemoryTimelineStore.class.getName());
   }
 
-  private static Object maybeConvert(Object o) {
-    if (o instanceof Long) {
-      Long l = (Long)o;
-      if (l >= Integer.MIN_VALUE && l <= Integer.MAX_VALUE) {
-        return l.intValue();
-      }
-    }
-    return o;
+  public MemoryTimelineStore(String name) {
+    super(name);
+    entities = new HashMapStoreAdapter<>();
+    entityInsertTimes = new HashMapStoreAdapter<>();
+    domainById = new HashMapStoreAdapter<>();
+    domainsByOwner = new HashMapStoreAdapter<>();
   }
 
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-applicationhistoryservice/src/main/java/org/apache/hadoop/yarn/server/timeline/TimelineStoreMapAdapter.java

@@ -0,0 +1,60 @@
+/**
+ * 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.hadoop.yarn.server.timeline;
+
+import java.util.Iterator;
+
+/**
+ * An adapter for map timeline store implementations
+ * @param <K> the type of the key set
+ * @param <V> the type of the value set
+ */
+interface TimelineStoreMapAdapter<K, V> {
+  /**
+   * @param key
+   * @return map(key)
+   */
+  V get(K key);
+
+  /**
+   * Add mapping key->value in the map
+   * @param key
+   * @param value
+   */
+  void put(K key, V value);
+
+  /**
+   * Remove mapping with key keyToRemove
+   * @param keyToRemove
+   */
+  void remove(K keyToRemove);
+
+  /**
+   * @return the iterator of the value set of the map
+   */
+  Iterator<V> valueSetIterator();
+
+  /**
+   * Return the iterator of the value set of the map, starting from minV if type
+   * V is comparable.
+   * @param minV
+   * @return
+   */
+  Iterator<V> valueSetIterator(V minV);
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-applicationhistoryservice/src/main/java/org/apache/hadoop/yarn/server/timeline/util/LeveldbUtils.java

@@ -19,6 +19,7 @@
 package org.apache.hadoop.yarn.server.timeline.util;
 
 
+import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.io.WritableComparator;
 
 import java.io.IOException;
@@ -177,4 +178,10 @@ public class LeveldbUtils {
         prefixlen) == 0;
   }
 
+  /**
+   * Default permission mask for the level db dir
+   */
+  public static final FsPermission LEVELDB_DIR_UMASK = FsPermission
+      .createImmutable((short) 0700);
+
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timeline-pluginstorage/pom.xml

@@ -132,5 +132,9 @@
       <artifactId>mockito-all</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>com.fasterxml.jackson.core</groupId>
+      <artifactId>jackson-databind</artifactId>
+    </dependency>
   </dependencies>
 </project>

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timeline-pluginstorage/src/main/java/org/apache/hadoop/yarn/server/timeline/EntityCacheItem.java

@@ -102,7 +102,8 @@ public class EntityCacheItem {
       }
       if (!appLogs.getDetailLogs().isEmpty()) {
         if (store == null) {
-          store = new MemoryTimelineStore();
+          store = new LevelDBCacheTimelineStore(groupId.toString(),
+              "LeveldbCache." + groupId);
           store.init(config);
           store.start();
         }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timeline-pluginstorage/src/main/java/org/apache/hadoop/yarn/server/timeline/LevelDBCacheTimelineStore.java

@@ -0,0 +1,316 @@
+/**
+ * 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.hadoop.yarn.server.timeline;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.classification.InterfaceAudience.Private;
+import org.apache.hadoop.classification.InterfaceStability.Unstable;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.io.IOUtils;
+import org.apache.hadoop.yarn.api.records.timeline.TimelineEntity;
+import org.apache.hadoop.yarn.conf.YarnConfiguration;
+import org.apache.hadoop.yarn.server.timeline.util.LeveldbUtils;
+import org.fusesource.leveldbjni.JniDBFactory;
+import org.iq80.leveldb.DB;
+import org.iq80.leveldb.DBIterator;
+import org.iq80.leveldb.Options;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.Iterator;
+import java.util.Map;
+
+/**
+ * LevelDB implementation of {@link KeyValueBasedTimelineStore}. This
+ * implementation stores the entity hash map into a LevelDB instance.
+ * There are two partitions of the key space. One partition is to store a
+ * entity id to start time mapping:
+ *
+ * i!ENTITY_ID!ENTITY_TYPE -> ENTITY_START_TIME
+ *
+ * The other partition is to store the actual data:
+ *
+ * e!START_TIME!ENTITY_ID!ENTITY_TYPE -> ENTITY_BYTES
+ *
+ * This storage does not have any garbage collection mechanism, and is designed
+ * mainly for caching usages.
+ */
+@Private
+@Unstable
+public class LevelDBCacheTimelineStore extends KeyValueBasedTimelineStore {
+  private static final Log LOG
+      = LogFactory.getLog(LevelDBCacheTimelineStore.class);
+  private static final String CACHED_LDB_FILE_PREFIX = "-timeline-cache.ldb";
+  private String dbId;
+  private DB entityDb;
+  private Configuration configuration;
+
+  public LevelDBCacheTimelineStore(String id, String name) {
+    super(name);
+    dbId = id;
+    entityInsertTimes = new MemoryTimelineStore.HashMapStoreAdapter<>();
+    domainById = new MemoryTimelineStore.HashMapStoreAdapter<>();
+    domainsByOwner = new MemoryTimelineStore.HashMapStoreAdapter<>();
+  }
+
+  public LevelDBCacheTimelineStore(String id) {
+    this(id, LevelDBCacheTimelineStore.class.getName());
+  }
+
+  @Override
+  protected void serviceInit(Configuration conf) throws Exception {
+    configuration = conf;
+    Options options = new Options();
+    options.createIfMissing(true);
+    options.cacheSize(conf.getLong(
+        YarnConfiguration.TIMELINE_SERVICE_LEVELDB_CACHE_READ_CACHE_SIZE,
+        YarnConfiguration.
+            DEFAULT_TIMELINE_SERVICE_LEVELDB_CACHE_READ_CACHE_SIZE));
+    JniDBFactory factory = new JniDBFactory();
+    Path dbPath = new Path(
+        conf.get(YarnConfiguration.TIMELINE_SERVICE_LEVELDB_PATH),
+        dbId + CACHED_LDB_FILE_PREFIX);
+    FileSystem localFS = null;
+
+    try {
+      localFS = FileSystem.getLocal(conf);
+      if (!localFS.exists(dbPath)) {
+        if (!localFS.mkdirs(dbPath)) {
+          throw new IOException("Couldn't create directory for leveldb " +
+              "timeline store " + dbPath);
+        }
+        localFS.setPermission(dbPath, LeveldbUtils.LEVELDB_DIR_UMASK);
+      }
+    } finally {
+      IOUtils.cleanup(LOG, localFS);
+    }
+    LOG.info("Using leveldb path " + dbPath);
+    entityDb = factory.open(new File(dbPath.toString()), options);
+    entities = new LevelDBMapAdapter<>(entityDb);
+
+    super.serviceInit(conf);
+  }
+
+  @Override
+  protected synchronized void serviceStop() throws Exception {
+    IOUtils.cleanup(LOG, entityDb);
+    Path dbPath = new Path(
+        configuration.get(YarnConfiguration.TIMELINE_SERVICE_LEVELDB_PATH),
+        dbId + CACHED_LDB_FILE_PREFIX);
+    FileSystem localFS = null;
+    try {
+      localFS = FileSystem.getLocal(configuration);
+      if (!localFS.delete(dbPath, true)) {
+          throw new IOException("Couldn't delete data file for leveldb " +
+              "timeline store " + dbPath);
+      }
+    } finally {
+      IOUtils.cleanup(LOG, localFS);
+    }
+    super.serviceStop();
+  }
+
+  /**
+   * A specialized hash map storage that uses LevelDB for storing entity id to
+   * entity mappings.
+   *
+   * @param <K> an {@link EntityIdentifier} typed hash key
+   * @param <V> a {@link TimelineEntity} typed value
+   */
+  static class LevelDBMapAdapter<K extends EntityIdentifier,
+      V extends TimelineEntity> implements TimelineStoreMapAdapter<K, V> {
+    private static final String TIME_INDEX_PREFIX = "i";
+    private static final String ENTITY_STORAGE_PREFIX = "e";
+    DB entityDb;
+
+    public LevelDBMapAdapter(DB currLevelDb) {
+      entityDb = currLevelDb;
+    }
+
+    @Override
+    public V get(K entityId) {
+      V result = null;
+      // Read the start time from the index
+      byte[] startTimeBytes = entityDb.get(getStartTimeKey(entityId));
+      if (startTimeBytes == null) {
+        return null;
+      }
+
+      // Build the key for the entity storage and read it
+      try {
+        result = getEntityForKey(getEntityKey(entityId, startTimeBytes));
+      } catch (IOException e) {
+        LOG.error("GenericObjectMapper cannot read key from key "
+            + entityId.toString()
+            + " into an object. Read aborted! ");
+        LOG.error(e.getMessage());
+      }
+
+      return result;
+    }
+
+    @Override
+    public void put(K entityId, V entity) {
+      Long startTime = entity.getStartTime();
+      if (startTime == null) {
+        startTime = System.currentTimeMillis();
+      }
+      // Build the key for the entity storage and read it
+      byte[] startTimeBytes = GenericObjectMapper.writeReverseOrderedLong(
+          startTime);
+      try {
+        byte[] valueBytes = GenericObjectMapper.write(entity);
+        entityDb.put(getEntityKey(entityId, startTimeBytes), valueBytes);
+      } catch (IOException e) {
+        LOG.error("GenericObjectMapper cannot write "
+            + entity.getClass().getName()
+            + " into a byte array. Write aborted! ");
+        LOG.error(e.getMessage());
+      }
+
+      // Build the key for the start time index
+      entityDb.put(getStartTimeKey(entityId), startTimeBytes);
+    }
+
+    @Override
+    public void remove(K entityId) {
+      // Read the start time from the index (key starts with an "i") then delete
+      // the record
+      LeveldbUtils.KeyBuilder startTimeKeyBuilder
+          = LeveldbUtils.KeyBuilder.newInstance();
+      startTimeKeyBuilder.add(TIME_INDEX_PREFIX).add(entityId.getId())
+          .add(entityId.getType());
+      byte[] startTimeBytes = entityDb.get(startTimeKeyBuilder.getBytes());
+      if (startTimeBytes == null) {
+        return;
+      }
+      entityDb.delete(startTimeKeyBuilder.getBytes());
+
+      // Build the key for the entity storage and delete it
+      entityDb.delete(getEntityKey(entityId, startTimeBytes));
+    }
+
+    @Override
+    public Iterator<V> valueSetIterator() {
+      return getIterator(null, Long.MAX_VALUE);
+    }
+
+    @Override
+    public Iterator<V> valueSetIterator(V minV) {
+      return getIterator(
+          new EntityIdentifier(minV.getEntityId(), minV.getEntityType()),
+          minV.getStartTime());
+    }
+
+    private Iterator<V> getIterator(
+        EntityIdentifier startId, long startTimeMax) {
+
+      final DBIterator internalDbIterator = entityDb.iterator();
+
+      // we need to iterate from the first element with key greater than or
+      // equal to ENTITY_STORAGE_PREFIX!maxTS(!startId), but stop on the first
+      // key who does not have prefix ENTITY_STORATE_PREFIX
+
+      // decide end prefix
+      LeveldbUtils.KeyBuilder entityPrefixKeyBuilder
+          = LeveldbUtils.KeyBuilder.newInstance();
+      entityPrefixKeyBuilder.add(ENTITY_STORAGE_PREFIX);
+      final byte[] prefixBytes = entityPrefixKeyBuilder.getBytesForLookup();
+      // decide start prefix on top of end prefix and seek
+      final byte[] startTimeBytes
+          = GenericObjectMapper.writeReverseOrderedLong(startTimeMax);
+      entityPrefixKeyBuilder.add(startTimeBytes, true);
+      if (startId != null) {
+        entityPrefixKeyBuilder.add(startId.getId());
+      }
+      final byte[] startPrefixBytes
+          = entityPrefixKeyBuilder.getBytesForLookup();
+      internalDbIterator.seek(startPrefixBytes);
+
+      return new Iterator<V>() {
+        @Override
+        public boolean hasNext() {
+          if (!internalDbIterator.hasNext()) {
+            return false;
+          }
+          Map.Entry<byte[], byte[]> nextEntry = internalDbIterator.peekNext();
+          if (LeveldbUtils.prefixMatches(
+              prefixBytes, prefixBytes.length, nextEntry.getKey())) {
+            return true;
+          }
+          return false;
+        }
+
+        @Override
+        public V next() {
+          if (hasNext()) {
+            Map.Entry<byte[], byte[]> nextRaw = internalDbIterator.next();
+            try {
+              V result = getEntityForKey(nextRaw.getKey());
+              return result;
+            } catch (IOException e) {
+              LOG.error("GenericObjectMapper cannot read key from key "
+                  + nextRaw.getKey()
+                  + " into an object. Read aborted! ");
+              LOG.error(e.getMessage());
+            }
+          }
+          return null;
+        }
+
+        // We do not support remove operations within one iteration
+        @Override
+        public void remove() {
+          LOG.error("LevelDB map adapter does not support iterate-and-remove"
+              + " use cases. ");
+        }
+      };
+    }
+
+    @SuppressWarnings("unchecked")
+    private V getEntityForKey(byte[] key) throws IOException {
+      byte[] resultRaw = entityDb.get(key);
+      if (resultRaw == null) {
+        return null;
+      }
+      ObjectMapper entityMapper = new ObjectMapper();
+      return (V) entityMapper.readValue(resultRaw, TimelineEntity.class);
+    }
+
+    private byte[] getStartTimeKey(K entityId) {
+      LeveldbUtils.KeyBuilder startTimeKeyBuilder
+          = LeveldbUtils.KeyBuilder.newInstance();
+      startTimeKeyBuilder.add(TIME_INDEX_PREFIX).add(entityId.getId())
+          .add(entityId.getType());
+      return startTimeKeyBuilder.getBytes();
+    }
+
+    private byte[] getEntityKey(K entityId, byte[] startTimeBytes) {
+      LeveldbUtils.KeyBuilder entityKeyBuilder
+          = LeveldbUtils.KeyBuilder.newInstance();
+      entityKeyBuilder.add(ENTITY_STORAGE_PREFIX).add(startTimeBytes, true)
+          .add(entityId.getId()).add(entityId.getType());
+      return entityKeyBuilder.getBytes();
+    }
+  }
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timeline-pluginstorage/src/test/java/org/apache/hadoop/yarn/server/timeline/PluginStoreTestUtils.java

@@ -200,7 +200,7 @@ class PluginStoreTestUtils {
   }
 
   static TimelineDataManager getTdmWithMemStore(Configuration config) {
-    TimelineStore store = new MemoryTimelineStore();
+    TimelineStore store = new MemoryTimelineStore("MemoryStore.test");
     TimelineDataManager tdm = getTdmWithStore(config, store);
     return tdm;
   }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timeline-pluginstorage/src/test/java/org/apache/hadoop/yarn/server/timeline/TestLevelDBCacheTimelineStore.java

@@ -0,0 +1,94 @@
+/**
+ * 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.hadoop.yarn.server.timeline;
+
+import org.apache.hadoop.yarn.conf.YarnConfiguration;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.IOException;
+
+public class TestLevelDBCacheTimelineStore extends TimelineStoreTestUtils {
+
+  @Before
+  public void setup() throws Exception {
+    store = new LevelDBCacheTimelineStore("app1");
+    store.init(new YarnConfiguration());
+    store.start();
+    loadTestEntityData();
+    loadVerificationEntityData();
+    loadTestDomainData();
+  }
+
+  @After
+  public void tearDown() throws Exception {
+    store.stop();
+  }
+
+  public TimelineStore getTimelineStore() {
+    return store;
+  }
+
+  @Test
+  public void testGetSingleEntity() throws IOException {
+    super.testGetSingleEntity();
+  }
+
+  @Test
+  public void testGetEntities() throws IOException {
+    super.testGetEntities();
+  }
+
+  @Test
+  public void testGetEntitiesWithFromId() throws IOException {
+    super.testGetEntitiesWithFromId();
+  }
+
+  @Test
+  public void testGetEntitiesWithFromTs() throws IOException {
+    super.testGetEntitiesWithFromTs();
+  }
+
+  @Test
+  public void testGetEntitiesWithPrimaryFilters() throws IOException {
+    super.testGetEntitiesWithPrimaryFilters();
+  }
+
+  @Test
+  public void testGetEntitiesWithSecondaryFilters() throws IOException {
+    super.testGetEntitiesWithSecondaryFilters();
+  }
+
+  @Test
+  public void testGetEvents() throws IOException {
+    super.testGetEvents();
+  }
+
+  @Test
+  public void testGetDomain() throws IOException {
+    super.testGetDomain();
+  }
+
+  @Test
+  public void testGetDomains() throws IOException {
+    super.testGetDomains();
+  }
+
+}