David Ribeiro Alves has posted comments on this change. ( http://gerrit.cloudera.org:8080/10503 )
Change subject: IMPALA-6812: Fix flaky Kudu scan tests ...................................................................... Patch Set 1: READ_AT_SNAPSHOT was reverted because it caused flakyness in stress tests iirc. Note also that both READ_AT_SNAPSHOT and READ_YOUR_WRITES need timestamp propagation between clients/queries to work properly. READ_AT_SNAPSHOT, while not consistent without timestamp propagation, effectively provided RYW by forcing the read to happen at now(), forcibly after the last write and without coordination. But READ_AT_SNAPSHOT requires an effective leader to work, which were sometimes missing in stress tests. I realize that impala added a kudu client cache to the backend. If that makes it so that the same client is used across different queries, then RYW should both solve consistency issues and be more lenient regarding leaderless tablets. If the same client is not always used, then RYW might help, but likely won't completely solve the problem. -- To view, visit http://gerrit.cloudera.org:8080/10503 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I70df84f2cbc663107f2ad029565d3c15bdfbd47c Gerrit-Change-Number: 10503 Gerrit-PatchSet: 1 Gerrit-Owner: Thomas Marshall <[email protected]> Gerrit-Reviewer: Dan Hecht <[email protected]> Gerrit-Reviewer: David Ribeiro Alves <[email protected]> Gerrit-Reviewer: Thomas Marshall <[email protected]> Gerrit-Reviewer: Tim Armstrong <[email protected]> Gerrit-Reviewer: Todd Lipcon <[email protected]> Gerrit-Comment-Date: Tue, 05 Jun 2018 18:54:47 +0000 Gerrit-HasComments: No
