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Posted to solr-user@lucene.apache.org by SOLR4189 <Kl...@yandex.ru> on 2018/02/13 17:17:43 UTC

Replicas: sending query to leader and replica simultaneously

Hi all,

I use SOLR-6.5.1 and I want to start to use replicas in SolrCloud mode. I
read ref guide and Solr in Action, and I want to make sure only one thing
about REPLICAS:

SOLR can't send query both to leader and to slave simultaneously and returns
the fastest response of them?

(in the case leader or slave is active, but one of them is overloaded and
responses a lot of time).

Thank you. 



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Re: Replicas: sending query to leader and replica simultaneously

Posted by SOLR4189 <Kl...@yandex.ru>.
Today I found something interesting that exists in ElasticSearch. It's called
Adaptive Replica Selection 
https://www.elastic.co/guide/en/elasticsearch/reference/6.1/search.html

Did you hear about it? Maybe exists something in SOLR? I think it's very
useful for my case.



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Re: Replicas: sending query to leader and replica simultaneously

Posted by SOLR4189 <Kl...@yandex.ru>.
Thank you, Emir for your answer

*But it will not send request to multiple replicas - that would be a waste
of resources.*
What if server is overloaded, but it is responsive? Then it will not be a
waste of resources, because second replica will response faster then
overloaded replica.


*and flag unresponsive one*
Until when it will marked unresponsive? If solr will check it every request,
it is also would be a waste of resources...





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Re: Replicas: sending query to leader and replica simultaneously

Posted by Emir Arnautović <em...@sematext.com>.
Hi,
Solr will loadbalance replicas and if one is unresponsive, send it to another and flag unresponsive one. But it will not send request to multiple replicas - that would be a waste of resources. If you want something like that, you would probably have to set up two separate clusters and send two requests from your client code.

HTH,
Emir
--
Monitoring - Log Management - Alerting - Anomaly Detection
Solr & Elasticsearch Consulting Support Training - http://sematext.com/



> On 13 Feb 2018, at 18:17, SOLR4189 <Kl...@yandex.ru> wrote:
> 
> Hi all,
> 
> I use SOLR-6.5.1 and I want to start to use replicas in SolrCloud mode. I
> read ref guide and Solr in Action, and I want to make sure only one thing
> about REPLICAS:
> 
> SOLR can't send query both to leader and to slave simultaneously and returns
> the fastest response of them?
> 
> (in the case leader or slave is active, but one of them is overloaded and
> responses a lot of time).
> 
> Thank you. 
> 
> 
> 
> --
> Sent from: http://lucene.472066.n3.nabble.com/Solr-User-f472068.html