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https://issues.apache.org/jira/browse/CASSANDRA-2103?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13051329#comment-13051329
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Yang Yang edited comment on CASSANDRA-2103 at 6/17/11 9:26 PM:
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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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