Sailesh Mukil has posted comments on this change. ( http://gerrit.cloudera.org:8080/9966 )
Change subject: IMPALA-6813: Hedged reads metrics broken when scanning non-HDFS based table ...................................................................... Patch Set 1: > > Patch Set 1: > > > > > Patch Set 1: > > > > > > I haven't added a custom cluster test for this since hedged > reads are not deterministic, and we'd be dealing with a bunch of > flakiness. > > > > I'm uncomfortable that we've got a flag with no testing of the > code path behind it. > > > > Can you force a hedged read by "kill -STOP"'ing a datanode before > the query and "kill -CONT" afterwards? > > Thanks for the suggestion, Phil. I will try this. I picked this up again and spent some time trying to force hedged reads. However, I found that even if you SIGSTOP any combination of DataNodes while leaving only one running, and then run a query against HDFS, since all the DataNodes are on the same node in a minicluster, it doesn't count them as hedged reads. This means that we can only have a hedged read test in a remote cluster setting. -- To view, visit http://gerrit.cloudera.org:8080/9966 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I48fe80dfd9a1ed68a8f2b7038e5f42b5a3df3baa Gerrit-Change-Number: 9966 Gerrit-PatchSet: 1 Gerrit-Owner: Sailesh Mukil <[email protected]> Gerrit-Reviewer: Philip Zeyliger <[email protected]> Gerrit-Reviewer: Sailesh Mukil <[email protected]> Gerrit-Comment-Date: Mon, 21 May 2018 21:56:39 +0000 Gerrit-HasComments: No
