GitHub user dhruve opened a pull request: https://github.com/apache/spark/pull/18691
[SPARK-21243][Core] Limit no. of map outputs in a shuffle fetch For configurations with external shuffle enabled, we have observed that if a very large no. of blocks are being fetched from a remote host, it puts the NM under extra pressure and can crash it. This change introduces a configuration `spark.reducer.maxBlocksInFlightPerAddress` , to limit the no. of map outputs being fetched from a given remote address. The changes applied here are applicable for both the scenarios - when external shuffle is enabled as well as disabled. Ran the job with the default configuration which does not change the existing behavior and ran it with few configurations of lower values -10,20,50,100. The job ran fine and there is no change in the output. (I will update the metrics related to NM in some time.) Author: Dhruve Ashar <dhruveas...@gmail.com> Closes #18487 from dhruve/impr/SPARK-21243. ## What changes were proposed in this pull request? (Please fill in changes proposed in this fix) ## How was this patch tested? (Please explain how this patch was tested. E.g. unit tests, integration tests, manual tests) (If this patch involves UI changes, please attach a screenshot; otherwise, remove this) Please review http://spark.apache.org/contributing.html before opening a pull request. You can merge this pull request into a Git repository by running: $ git pull https://github.com/dhruve/spark branch-2.2 Alternatively you can review and apply these changes as the patch at: https://github.com/apache/spark/pull/18691.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 #18691 ---- commit 036eb17d32c1b9b0f76ab9c0c4a10f6248728476 Author: Dhruve Ashar <dhruveas...@gmail.com> Date: 2017-07-19T20:53:28Z [SPARK-21243][Core] Limit no. of map outputs in a shuffle fetch For configurations with external shuffle enabled, we have observed that if a very large no. of blocks are being fetched from a remote host, it puts the NM under extra pressure and can crash it. This change introduces a configuration `spark.reducer.maxBlocksInFlightPerAddress` , to limit the no. of map outputs being fetched from a given remote address. The changes applied here are applicable for both the scenarios - when external shuffle is enabled as well as disabled. Ran the job with the default configuration which does not change the existing behavior and ran it with few configurations of lower values -10,20,50,100. The job ran fine and there is no change in the output. (I will update the metrics related to NM in some time.) Author: Dhruve Ashar <dhruveas...@gmail.com> Closes #18487 from dhruve/impr/SPARK-21243. ---- --- 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