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From "Sylvain Lebresne (JIRA)" <>
Subject [jira] Commented: (CASSANDRA-1546) (Yet another) approach to counting
Date Tue, 26 Oct 2010 20:04:25 GMT


Sylvain Lebresne commented on CASSANDRA-1546:

Thinking a bit more on this unboostrap thing, I'm wondering if adding a fix
post-streaming is the right solution. I fear it is too fragile. Because when a
node receives ranges for which he was responsible before, we should make sure
it don't get the same info from two nodes, or that he don't have still the
range locally (because repair wasn't run for instance). Otherwise there is a
risk to break the counter (counting twice the same value). Opinions ?

Another solution I can see that I think wouldn't have this problem would be to
make nodes regenerate a new node id (easy if we use uuids) each time the ranges
they are responsible for changes (at least, when it grows). The only problem I
see with that is that it will make the counters grow (more columns for a given
counter) over time, because we'll accumulate column for node ids that are not
used anymore. But I don't think it would be too hard to merge the columns for
those forsaken node id. Does that make sense ?

> (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: 0.7.1
>         Attachments: 0001-v2-Remove-IClock-from-internals.patch, 0001-v3-Remove-IClock-from-internals.txt,
0001-v4-Counters.patch, 0002-v2-Counters.patch, 0002-v3-Counters.txt, 0002-v4-thrift-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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