HeartSaVioR commented on a change in pull request #19096: [SPARK-21869][SS] A
cached Kafka producer should not be closed if any task is using it - adds inuse
tracking.
URL: https://github.com/apache/spark/pull/19096#discussion_r270609811
##########
File path:
external/kafka-0-10-sql/src/main/scala/org/apache/spark/sql/kafka010/CachedKafkaProducer.scala
##########
@@ -40,81 +90,114 @@ private[kafka010] object CachedKafkaProducer extends
Logging {
"spark.kafka.producer.cache.timeout",
s"${defaultCacheExpireTimeout}ms")).getOrElse(defaultCacheExpireTimeout)
- private val cacheLoader = new CacheLoader[Seq[(String, Object)], Producer] {
- override def load(config: Seq[(String, Object)]): Producer = {
- val configMap = config.map(x => x._1 -> x._2).toMap.asJava
- createKafkaProducer(configMap)
+ private val cacheLoader = new CacheLoader[Seq[(String, Object)],
CachedKafkaProducer] {
+ override def load(params: Seq[(String, Object)]): CachedKafkaProducer = {
+ CachedKafkaProducer(kafkaParams = params)
}
}
- private val removalListener = new RemovalListener[Seq[(String, Object)],
Producer]() {
+ private val closeQueue = new ConcurrentLinkedQueue[CachedKafkaProducer]()
+
+ private val removalListener = new RemovalListener[Seq[(String, Object)],
CachedKafkaProducer]() {
override def onRemoval(
- notification: RemovalNotification[Seq[(String, Object)], Producer]):
Unit = {
- val paramsSeq: Seq[(String, Object)] = notification.getKey
- val producer: Producer = notification.getValue
- logDebug(
- s"Evicting kafka producer $producer params: $paramsSeq, due to
${notification.getCause}")
- close(paramsSeq, producer)
+ notification: RemovalNotification[Seq[(String, Object)],
CachedKafkaProducer]): Unit = {
+ val producer: CachedKafkaProducer = notification.getValue
+ if (producer.inUse()) {
+ logDebug(s"Evicting kafka producer $producer, due to
${notification.getCause}.")
+ // When `inuse` producer is evicted we wait for it to be released
before finally closing it.
+ closeQueue.add(producer)
+ producer.unCache()
+ } else {
+ close(producer)
+ }
}
}
- private lazy val guavaCache: LoadingCache[Seq[(String, Object)], Producer] =
+ private lazy val guavaCache: LoadingCache[Seq[(String, Object)],
CachedKafkaProducer] =
CacheBuilder.newBuilder().expireAfterAccess(cacheExpireTimeout,
TimeUnit.MILLISECONDS)
.removalListener(removalListener)
- .build[Seq[(String, Object)], Producer](cacheLoader)
-
- private def createKafkaProducer(producerConfiguration: ju.Map[String,
Object]): Producer = {
- val updatedKafkaProducerConfiguration =
- KafkaConfigUpdater("executor", producerConfiguration.asScala.toMap)
- .setAuthenticationConfigIfNeeded()
- .build()
- val kafkaProducer: Producer = new
Producer(updatedKafkaProducerConfiguration)
- logDebug(s"Created a new instance of KafkaProducer for
$updatedKafkaProducerConfiguration.")
- kafkaProducer
- }
+ .build[Seq[(String, Object)], CachedKafkaProducer](cacheLoader)
/**
* Get a cached KafkaProducer for a given configuration. If matching
KafkaProducer doesn't
* exist, a new KafkaProducer will be created. KafkaProducer is thread safe,
it is best to keep
* one instance per specified kafkaParams.
*/
- private[kafka010] def getOrCreate(kafkaParams: ju.Map[String, Object]):
Producer = {
- val paramsSeq: Seq[(String, Object)] = paramsToSeq(kafkaParams)
+ private[kafka010] def acquire(kafkaParamsMap: ju.Map[String, Object]):
CachedKafkaProducer = {
+ val paramsSeq: Seq[(String, Object)] = paramsToSeq(kafkaParamsMap)
try {
- guavaCache.get(paramsSeq)
+ val producer = this.synchronized {
+ val cachedKafkaProducer: CachedKafkaProducer =
guavaCache.get(paramsSeq)
+ cachedKafkaProducer.inUseCount.incrementAndGet()
+ logDebug(s"Granted producer $cachedKafkaProducer")
+ cachedKafkaProducer
+ }
+ producer
} catch {
- case e @ (_: ExecutionException | _: UncheckedExecutionException | _:
ExecutionError)
+ case e@(_: ExecutionException | _: UncheckedExecutionException | _:
ExecutionError)
if e.getCause != null =>
throw e.getCause
}
}
- private def paramsToSeq(kafkaParams: ju.Map[String, Object]): Seq[(String,
Object)] = {
- val paramsSeq: Seq[(String, Object)] = kafkaParams.asScala.toSeq.sortBy(x
=> x._1)
+ private def paramsToSeq(kafkaParamsMap: ju.Map[String, Object]):
Seq[(String, Object)] = {
+ val paramsSeq: Seq[(String, Object)] =
kafkaParamsMap.asScala.toSeq.sortBy(x => x._1)
paramsSeq
}
- /** For explicitly closing kafka producer */
- private[kafka010] def close(kafkaParams: ju.Map[String, Object]): Unit = {
- val paramsSeq = paramsToSeq(kafkaParams)
- guavaCache.invalidate(paramsSeq)
+ /* Release a kafka producer back to the kafka cache. We simply decrement
it's inuse count. */
+ private[kafka010] def release(producer: CachedKafkaProducer, failing:
Boolean): Unit = {
+ this.synchronized {
+ // It should be ok to call release multiple times on the same producer
object.
+ if (producer.inUse()) {
+ // So that we do not end up with -ve in-use counts.
+ producer.inUseCount.decrementAndGet()
+ logDebug(s"Released producer $producer.")
+ } else {
+ logWarning(s"Tried to release a not in use producer, $producer.")
+ }
+ if (failing) {
+ // If this producer is failing to write, we remove it from cache.
+ // So that it is re-created, eventually.
+ val cachedProducer = guavaCache.getIfPresent(producer.kafkaParams)
+ if (cachedProducer != null && cachedProducer.id == producer.id) {
+ logDebug(s"Invalidating a failing producer: $producer.")
+ guavaCache.invalidate(producer.kafkaParams)
+ }
+ }
+ }
+ if (!producer.inUse() && !producer.isCached) {
Review comment:
And I feel complicated that there're two different places which close
producer.
Every producers are cached, and all the producers will be go through removal
listener to be removed in cache and be closed immediately or added to close
queue to be closed eventually (when it fulfills the condition).
Then from outer removal listener we just need to concern about how to handle
close queue. The if statement here makes us to determine when to handle close
queue immediately, but there's race condition I described before so it's not
exactly correct.
(Actually if it's exactly thread-safe we even don't need a close queue. Just
release it once if conditions are met.)
Other approach would be injecting cleanup of close queue to the end of
`release` method with some probability (Guava cache seems to evict like this
way), or even periodically in background thread. Handling close queue doesn't
need to be synchronized with others (if we avoid concurrent modification
exception) - only thing would be `inUse` in producer, but once we revisit the
producer eventually (not too late) no need to be exact.
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