Ngone51 commented on code in PR #47197: URL: https://github.com/apache/spark/pull/47197#discussion_r1663730445
########## core/src/main/scala/org/apache/spark/executor/TaskMetrics.scala: ########## @@ -264,12 +264,37 @@ class TaskMetrics private[spark] () extends Serializable { /** * External accumulators registered with this task. */ - @transient private[spark] lazy val _externalAccums = new CopyOnWriteArrayList[AccumulatorV2[_, _]] + @transient private[spark] lazy val _externalAccums = new ArrayBuffer[AccumulatorV2[_, _]] - private[spark] def externalAccums = _externalAccums.asScala + private[spark] def externalAccums: Seq[AccumulatorV2[_, _]] = withReadLock { + _externalAccums.toSeq Review Comment: It's cheap. It essentially creates a linked list without clone items. The complexity is O(n). -- 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: reviews-unsubscr...@spark.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org