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From sankalp kohli <kohlisank...@gmail.com>
Subject Re: How to avoid inter-dc read requests
Date Sun, 21 Jul 2013 20:41:32 GMT
Slice query does not trigger background read repair.
Implement Read Repair on Range
Queries<https://issues.apache.org/jira/browse/CASSANDRA-967>


On Sun, Jul 21, 2013 at 1:40 PM, sankalp kohli <kohlisankalp@gmail.com>wrote:

> There can be multiple reasons for that
> 1) Background read repairs.
> 2) Your data is not consistent and leading to read repairs.
> 3) For writes, irrespective of the consistency used, a single write
> request will goto other DC
> 4) You might be running other nodetools commands like repair.
> read_repair_chanceĀ¶<http://www.datastax.com/docs/1.2/configuration/storage_configuration#read-repair-chance>
>
> (Default: 0.1 or 1) Specifies the probability with which read repairs
> should be invoked on non-quorum reads. The value must be between 0 and 1.
> For tables created in versions of Cassandra before 1.0, it defaults to 1.
> For tables created in versions of Cassandra 1.0 and higher, it defaults to
> 0.1. However, for Cassandra 1.0, the default is 1.0 if you use CLI or any
> Thrift client, such as Hector or pycassa, and is 0.1 if you use CQL.
>
>
> On Sun, Jul 21, 2013 at 10:26 AM, Omar Shibli <omar@eyeviewdigital.com>wrote:
>
>> One more thing, I'm doing a lot of key slice read requests, is that
>> supposed to change anything?
>>
>>
>> On Sun, Jul 21, 2013 at 8:21 PM, Omar Shibli <omar@eyeviewdigital.com>wrote:
>>
>>> I'm seeing a lot of inter-dc read requests, although I've followed
>>> DataStax guidelines for multi-dc deployment
>>> http://www.datastax.com/dev/blog/deploying-cassandra-across-multiple-data-centers
>>>
>>> Here is my setup:
>>> 2 data centers within the same region (AWS)
>>> Targeting DC, RP 3, 6 nodes
>>> Analytic DC, RP 3, 11 nodes
>>>
>>> All the read/write request are issued with CL local quorum, but still
>>> there're a lot of inter-dc read request.
>>> Any suggestion, or am I missing something?
>>>
>>> Thanks in advance,
>>>
>>
>>
>

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