GitHub user brkyvz opened a pull request: https://github.com/apache/spark/pull/17543
[SPARK-20230] FetchFailedExceptions should invalidate file caches in MapOutputTracker even if newer stages are launched ## What changes were proposed in this pull request? If you lose instances that have shuffle outputs, you will start observing messages like: ``` 17/03/24 11:49:23 WARN TaskSetManager: Lost task 0.0 in stage 64.1 (TID 3849, 172.128.196.240, executor 0): FetchFailed(BlockManagerId(4, 172.128.200.157, 4048, None), shuffleId=16, mapId=2, reduceId=3, message= ``` Generally, these messages are followed by: ``` 17/03/24 11:49:23 INFO DAGScheduler: Executor lost: 4 (epoch 20) 17/03/24 11:49:23 INFO BlockManagerMasterEndpoint: Trying to remove executor 4 from BlockManagerMaster. 17/03/24 11:49:23 INFO BlockManagerMaster: Removed 4 successfully in removeExecutor 17/03/24 11:49:23 INFO DAGScheduler: Shuffle files lost for executor: 4 (epoch 20) 17/03/24 11:49:23 INFO ShuffleMapStage: ShuffleMapStage 63 is now unavailable on executor 4 (73/89, false) ``` which is great. Spark resubmits tasks for data that has been lost. However, if you have cascading instance failures, then you may come across: ``` 17/03/24 11:48:39 INFO DAGScheduler: Ignoring fetch failure from ResultTask(64, 46) as it's from ResultStage 64 attempt 0 and there is a more recent attempt for that stage (attempt ID 1) running ``` which don't invalidate file outputs. In later retries of the stage, Spark will attempt to access files on machines that don't exist anymore, and then after 4 tries, Spark will give up. If it had not ignored the fetch failure, and invalidated the cache, then most of the lost files could have been computed during one of the previous retries. ## How was this patch tested? Will add tests based on feedback You can merge this pull request into a Git repository by running: $ git pull https://github.com/brkyvz/spark SPARK-20230 Alternatively you can review and apply these changes as the patch at: https://github.com/apache/spark/pull/17543.patch To close this pull request, make a commit to your master/trunk branch with (at least) the following in the commit message: This closes #17543 ---- commit bc80aab919cabe93c59a312e7e72ed1ed453906d Author: Burak Yavuz <brk...@gmail.com> Date: 2017-04-05T19:14:22Z invalidate files ---- --- If your project is set up for it, you can reply to this email and have your reply appear on GitHub as well. If your project does not have this feature enabled and wishes so, or if the feature is enabled but not working, please contact infrastructure at infrastruct...@apache.org or file a JIRA ticket with INFRA. --- --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org