[jira] [Commented] (CASSANDRA-6194) speculative retry can sometimes violate consistency

["Brandon Williams (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-6194?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13793755#comment-13793755 ] 

Brandon Williams commented on CASSANDRA-6194:
---------------------------------------------

Unfortunately I haven't been able to repro manually and ccm has a problem with logging at debug on 2.0+ currently.  10 iterations of the test should be enough to trigger, though I bisected again to the same point with 30.

> speculative retry can sometimes violate consistency
> ---------------------------------------------------
>
>                 Key: CASSANDRA-6194
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-6194
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>            Reporter: Brandon Williams
>             Fix For: 2.0.2
>
>
> This is most evident with intermittent failures of the short_read dtests.  I'll focus on short_read_reversed_test for explanation, since that's what I used to bisect.  This test inserts some columns into a row, then deletes a subset, but it performs each delete on a different node, with another node down (hints are disabled.)  Finally it reads the row back at QUORUM and checks that it doesn't see any deleted columns, however with speculative retry on this often fails.  I bisected this to the change that made 99th percentile SR the default reliably by looping the test enough times at each iteration to be sure it was passing or failing.



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