Re: AW: Why does CockroachDB github website say Cassandra has noAvailability on datacenter failure?

[Amit Trivedi]

It indeed is a marketing gimmick. By clubbing Cassandra with likes of HBase 
that favors consistency over availability, points under cons section are all 
true, just not true when applied to any one database from that group.

Thanks and Regards

Amit Trivedi

On Feb 7, 2017, 7:32 AM -0500, j.kes...@enercast.de, wrote:
> Deeper inside there is a diagram:
>
> https://raw.githubusercontent.com/cockroachdb/cockroach/master/docs/media/sql-nosql-newsql.png
>
> They compare to NoSQL along with Riak, HBase and Cassandra.
>
> Of course you CAN have a Cassandra cluster which is not fully available with 
> loss of a dc nor consistent.
>
> Marketing 
>
> Gesendet von meinem Windows 10 Phone
>
> Von: DuyHai Doan
> Gesendet: Dienstag, 7. Februar 2017 11:53
> An: d...@cassandra.apache.org
> Cc: user@cassandra.apache.org
> Betreff: Re: Why does CockroachDB github website say Cassandra has 
> noAvailability on datacenter failure?
>
> The link you posted doesn't say anything about Cassandra
> Le 7 févr. 2017 11:41, "Kant Kodali" <k...@peernova.com> a écrit :
> Why does CockroachDB github website say Cassandra has no Availability on
> datacenter failure?
>
> https://github.com/cockroachdb/cockroach
>

Re: Where to change the datacenter name?

[Amit Trivedi]

I believe it is coming from system.local. You can verify by executing

select data_center from system.local;

I would be careful changing datacenter name, particularly in production. This
is essentially because if change of datacenter requires snitch
configuration change, it may result in stale data depending on token values
and snitch settings and there is a risk of node reporting invalid/ missing
data to client.



On Mon, Oct 10, 2016 at 4:08 PM, Ali Akhtar  wrote:

> So I see this:
>
> cluster_name: 'Test Cluster'
>
> But when I grep -i or ctrl + f for 'datacenter1` in cassandra.yaml, I
> don't see that anywhere except in a comment.
>
>
> Yet when I do nodetool status, I see: datacenter1
>
> And unless I define my replication as: '{'class':
> 'NetworkTopologyStrategy', 'datacenter1' : 3}' when creating my keyspace,
> my inserts / selects don't work because it says 0 replicas available (i.e
> if i use anything other than 'datacenter1' in the above stmt)
>
> I don't see 'datacenter1' in rackdc.properties. So my question is, which
> file contains 'datacenter1'?
>
> On Tue, Oct 11, 2016 at 12:54 AM, Adam Hutson  wrote:
>
>> There is a cluster name in the cassandra.yaml for naming the cluster, aka
>> data center. Then you assign keyspaces to the data center within the CREATE
>> KEYSPACE stmt with NetworkTopology.
>>
>>
>> On Monday, October 10, 2016, Ali Akhtar  wrote:
>>
>>> Where can I change the default name 'datacenter1'? I've looked through
>>> the configuration files in /etc/cassandra , and can't find where this value
>>> is being defined.
>>>
>>
>>
>> --
>>
>> Adam Hutson
>> Data Architect | DataScale
>> +1 (417) 224-5212
>> a...@datascale.io
>>
>
>

Using Spring Data Cassandra with Spring Boot Batch

[Amit Trivedi]

Hi,

I am wondering if anyone has used or tried using Spring data Cassandra with
Spring Batch or Spring book batch. I understand that Spring batch today
only supports RDBMS to store its metadata and only way I is to either
provide a relational database as datasource for spring batch or use an
embedded database (like H2 of HSQL).

Is it possible to create spring batch metadata tables in Cassandra and use
these instead? I guess the answer that to do this spring batch code needs
to be modified to support Cassandra.

Thanks
AT

Can Sqoop be used in cassandra only cluster for data migration?

[Amit Trivedi]

I am working on a POC and would like to move data from a relational
database to Cassandra. I was wondering if I can use Sqoop for this since it
is one time thing and it would be easy to just give a select query to Sqoop
to pull data from relational database.
However, it looks like I need to setup a new analytics (Hadoop) cluster to
use Sqoop. Is there any way to use Sqoop in cassandra only node? I am on
DSE 4.8.1

I know there are other ways to migrate data like using sstable loader or
COPY command (I am looking moving less than million rows).