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From "zhu han (JIRA)" <>
Subject [jira] Commented: (CASSANDRA-1546) (Yet another) approach to counting
Date Sat, 09 Oct 2010 01:56:33 GMT


zhu han commented on CASSANDRA-1546:

I wasn't clear in the last comment--the comments were UUID-specific.

Kelvin, I was not clear that your questions are UUID-specific. So my question is generic.
No matter UUID is used or not, IMHO, there is read on the write path. You should get the latest
value of local columns (read), and then apply the increment to it, write the local column
to memtable.  Sylvain gave detailed explanation [here|].

 Although the read of local column is not protected by synchronized block, it may trigger
disk seek and downgrade the performance on write path.  Does #1072 has the same problem? 

> (Yet another) approach to counting
> ----------------------------------
>                 Key: CASSANDRA-1546
>                 URL:
>             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,
> 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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