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From "Stefania (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-9949) maxPurgeableTimestamp needs to check memtables too
Date Mon, 11 Jan 2016 15:37:39 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-9949?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15092139#comment-15092139
] 

Stefania commented on CASSANDRA-9949:
-------------------------------------

Thanks for clarifying the fix version. 

Re. performance are you concerned by the loop on all cells in a column family? We could approximate
the min timestamp with the memtable creation time but I don't think this is a good approximation
and it's probably wrong if we receive a partition from a remote host with an older timestamp.
Storing the minimum timestamp in a column family and keeping it up-to-date requires a bit
of work but we can go down this route if it is the correct choice. However I feel there may
be a different approximation that I am missing.

I also could use some hints on how to test this. Do you think a dtest is achievable? I'm not
so sure how easy it is to simulate a 'very-out-of-order' write.

> maxPurgeableTimestamp needs to check memtables too
> --------------------------------------------------
>
>                 Key: CASSANDRA-9949
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-9949
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Local Write-Read Paths
>            Reporter: Jonathan Ellis
>            Assignee: Stefania
>             Fix For: 2.1.x, 2.2.x
>
>
> overlapIterator/maxPurgeableTimestamp don't include the memtables, so a very-out-of-order
write could be ignored



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