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From "Yang Yang (JIRA)" <j...@apache.org>
Subject [jira] [Issue Comment Edited] (CASSANDRA-2103) expiring counter columns
Date Fri, 17 Jun 2011 21:27:47 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-2103?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13051329#comment-13051329
] 

Yang Yang edited comment on CASSANDRA-2103 at 6/17/11 9:26 PM:
---------------------------------------------------------------

there could be a problem with trying to rely on forcing compaction order:

if you base the intended order on max timestamp of each sstable, the timestamp is not trustworthy,
because a single malicious client request can bump up its timestamp to the future, and arbitrarily
change the order of compaction, thus rendering the approach in 2735 useless.

you can't base the order on the physical sstable flush time either, since different nodes
have different flush times.

overall I think trying to fix the compaction order is not the correction direction to attack
this problem: the issue here is due to the changing order between *individual counter adds*,
this order can be different between different counters, so you have to fix the order between
the updates within each counter, *not the order between ensembles of counters*. such ensembles
of counters do not guarantee any orders at all, due to randomness in flushing time, or message
delivery (they have similar effects)



      was (Author: yangyangyyy):
    there could be a problem with trying to rely on forcing compaction order:

if you base the intended order on max timestamp of each sstable, the timestamp is not trustworthy,
because a single malicious client request can bump up its timestamp to the future, and arbitrarily
change the order of compaction, thus rendering the approach in 2735 useless.
  
> expiring counter columns
> ------------------------
>
>                 Key: CASSANDRA-2103
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-2103
>             Project: Cassandra
>          Issue Type: New Feature
>          Components: Core
>    Affects Versions: 0.8 beta 1
>            Reporter: Kelvin Kakugawa
>         Attachments: 0001-CASSANDRA-2103-expiring-counters-logic-tests.patch
>
>
> add ttl functionality to counter columns.

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