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From Sam Overton <sover...@acunu.com>
Subject Re: What is the nodeId for?
Date Wed, 20 Jul 2011 12:00:13 GMT
The NodeId is used in counter replication. Counters are stored on each
replica as a set of "shards," where each shard corresponds to the local
count of one of the replicas for that counter, as identified by the NodeId.

A NodeId is generated the first time cassandra starts, and might be renewed
during cleanup, or if you explicitly tell cassandra to generate a new one by
starting it with -D*cassandra*.renew_counter_id

Do either of the NodeIds in the CurrentLocal row also appear in the Local
row of the NodeIdInfo CF? the Local row is a history of previous NodeIds
belonging to this node. If one appears in the history and the other does
not, it is probably safe to assume that the old NodeId was not deleted from
the CurrentLocal row correctly, and so you could try removing it from there
manually.

Sam
--
Sam Overton
Acunu | http://www.acunu.com | @acunu

On 20 July 2011 12:25, Boris Yen <yulinyen@gmail.com> wrote:

> Hi,
>
> I think we might have screwed our data up. I saw multiple columns inside
> record: System.NodeIdInfo.CurrentLocal. It makes our cassandra dead forever.
> I was wondering if anyone could tell me what the NodeId is for? so that I
> might be able to duplicate this.
>
> Thanks in advance
> Boris
>

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