incubator-cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Boris Yen <yulin...@gmail.com>
Subject Re: What is the nodeId for?
Date Wed, 20 Jul 2011 13:47:17 GMT
Hi Sam,

Thanks for the explanation.

The NodeIds do appear in the Local row of NodeIdInfo, and after manually
deleting two (I got three before I deleted them) of them from CurrentLocal
row, the cassandra can be restarted now. I was just thinking what could be
the possible cause for this? and wondering if anyone has any idea about
this?

Boris

On Wed, Jul 20, 2011 at 8:00 PM, Sam Overton <soverton@acunu.com> wrote:

> 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
>>
>
>

Mime
View raw message