YARN-5340. Fixed a race condition in RollingLevelDBTimelineStore that caused loss of Timeline events. Contributed by Li Lu.

This commit is contained in:
Vinod Kumar Vavilapalli 2016-07-20 08:36:36 -07:00
parent 37362c2f92
commit 1c9d2ab503
1 changed files with 20 additions and 19 deletions

View File

@ -1243,8 +1243,7 @@ public class RollingLevelDBTimelineStore extends AbstractService implements
* Get the unique start time for a given entity as a byte array that sorts the
* timestamps in reverse order (see
* {@link GenericObjectMapper#writeReverseOrderedLong(long)}). If the start
* time doesn't exist, set it based on the information provided. Should only
* be called when a lock has been obtained on the entity.
* time doesn't exist, set it based on the information provided.
*
* @param entityId
* The id of the entity
@ -1257,8 +1256,9 @@ public class RollingLevelDBTimelineStore extends AbstractService implements
* @return A StartAndInsertTime
* @throws IOException
*/
private Long getAndSetStartTime(String entityId, String entityType,
Long startTime, List<TimelineEvent> events) throws IOException {
private Long getAndSetStartTime(String entityId,
String entityType, Long startTime, List<TimelineEvent> events)
throws IOException {
EntityIdentifier entity = new EntityIdentifier(entityId, entityType);
Long time = startTimeWriteCache.get(entity);
if (time != null) {
@ -1282,28 +1282,29 @@ public class RollingLevelDBTimelineStore extends AbstractService implements
* Checks db for start time and returns it if it exists. If it doesn't exist,
* writes the suggested start time (if it is not null). This is only called
* when the start time is not found in the cache, so it adds it back into the
* cache if it is found. Should only be called when a lock has been obtained
* on the entity.
* cache if it is found.
*/
private Long checkStartTimeInDb(EntityIdentifier entity,
Long suggestedStartTime) throws IOException {
Long startAndInsertTime = null;
// create lookup key for start time
byte[] b = createStartTimeLookupKey(entity.getId(), entity.getType());
// retrieve value for key
byte[] v = starttimedb.get(b);
if (v == null) {
// start time doesn't exist in db
if (suggestedStartTime == null) {
return null;
}
startAndInsertTime = suggestedStartTime;
synchronized (this) {
// retrieve value for key
byte[] v = starttimedb.get(b);
if (v == null) {
// start time doesn't exist in db
if (suggestedStartTime == null) {
return null;
}
startAndInsertTime = suggestedStartTime;
// write suggested start time
starttimedb.put(b, writeReverseOrderedLong(suggestedStartTime));
} else {
// found start time in db, so ignore suggested start time
startAndInsertTime = readReverseOrderedLong(v, 0);
// write suggested start time
starttimedb.put(b, writeReverseOrderedLong(suggestedStartTime));
} else {
// found start time in db, so ignore suggested start time
startAndInsertTime = readReverseOrderedLong(v, 0);
}
}
startTimeWriteCache.put(entity, startAndInsertTime);
startTimeReadCache.put(entity, startAndInsertTime);