Thomas Marshall has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/10503 )

Change subject: IMPALA-6812: Fix flaky Kudu scan tests
......................................................................


Patch Set 1:

As Tim said, Impala keeps track of KuduClient::GetLatestObservedTimestamp() on 
a per-session basis and propagates it around to all impalads. Having RYW 
consistency at the session level would be sufficient for our purposes here.

Impala also uses just a single KuduClient per impalad, though of course a scan 
may be performed by multiple impalads in parallel.

So it sounds like going to READ_YOUR_WRITES is the right way forward, at least 
for tests.

There's still a question of if we want to set that as the default, given things 
like: is there a perf cost for the extra consistency that the typical user 
might not want to pay? Would changing this default count as a breaking change 
that we might not want to do just in a random release?


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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: Wed, 06 Jun 2018 18:59:05 +0000
Gerrit-HasComments: No

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