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From "Kelvin Kakugawa (JIRA)" <j...@apache.org>
Subject [jira] Issue Comment Edited: (CASSANDRA-1546) (Yet another) approach to counting
Date Wed, 06 Oct 2010 17:44:33 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-1546?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12918606#action_12918606
] 

Kelvin Kakugawa edited comment on CASSANDRA-1546 at 10/6/10 1:43 PM:
---------------------------------------------------------------------

I read through your note on the v3 marker strategy.  It sounds reasonable and does address
the concerns that I raised, earlier.

I think it's worth it for you to highlight the potential drawbacks.  The three that seem to
stick out the most are:
1) it requires 1-2 reads in a synchronized code path, which doesn't gel w/ cassandra's write-optimized
design,
2) over-counts are repaired in an eventually consistent manner, and
3) UUIDs are only maintained for a configurable TTL.

The above aren't showstoppers.  However, anyone interested in using UUIDs to track updates
should be aware of their limitations + trade-offs.

      was (Author: kelvin):
    I read through your note on the v3 marker strategy.  It sounds reasonable and does address
the concerns that I raised, earlier.

I think it's worth it for you to highlight the potential drawbacks.  The three that seem to
stick out the most are:
1) it requires 1-2 reads in a synchronized method, which doesn't gel w/ cassandra's write-optimized
design,
2) over-counts are repaired in an eventually consistent manner, and
3) UUIDs are only maintained for a configurable TTL.

The above aren't showstoppers.  However, anyone interested in using UUIDs to track updates
should be aware of their limitations + trade-offs.
  
> (Yet another) approach to counting
> ----------------------------------
>
>                 Key: CASSANDRA-1546
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-1546
>             Project: Cassandra
>          Issue Type: New Feature
>          Components: Core
>            Reporter: Sylvain Lebresne
>            Assignee: Sylvain Lebresne
>             Fix For: 0.7.0
>
>         Attachments: 0001-Remove-IClock-from-internals.patch, 0001-v2-Remove-IClock-from-internals.patch,
0001-v3-Remove-IClock-from-internals.txt, 0002-Counters.patch, 0002-v2-Counters.patch, 0002-v3-Counters.txt,
0003-Generated-thrift-files-changes.patch, 0003-v2-Thrift-changes.patch, 0003-v3-Thrift-changes.txt,
marker_idea.txt
>
>
> This could be described as a mix between CASSANDRA-1072 without clocks and CASSANDRA-1421.
> More details in the comment below.

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