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From "Tracy Liang (BLOOMBERG/ 731 LEX)" <tlian...@bloomberg.net>
Subject Re: Is it possible to enable both REPLICATED and PARTITIONED?
Date Mon, 10 Oct 2016 17:54:20 GMT
Thanks for this clear explanation, Alexey. Basically I want to use Ignite as a shared in-memory
layer among multiple Spark Server instances. Also I have another question: does ignite cache
support predicate pushdown or a logic view of cache? For example, I only want certain column
of the value instead of returning the entire universe. How do I do that?

From: user@ignite.apache.org 
Subject: Re: Is it possible to enable both REPLICATED and PARTITIONED?

Tracy,

First of all, cache mode and number of backups could be set only once - on cache start.
So, if you know the size of your cluster you could set number of backups before cache start.
But, I think it is not reasonable to set number of backups equals to number of nodes.
If you need 100% high availability, just use replicated cache. But I would recommend to think
about how many nodes at once can be lost?
May be it is reasonable to set backups = 2? The more backups you choose - the more memory
will be consumed by backup partitions and also
grid will spend time in rebalancing data.
What is your use case?


On Mon, Oct 10, 2016 at 11:18 PM, Tracy Liang (BLOOMBERG/ 731 LEX) <tliang36@bloomberg.net>
wrote:

Thanks, and PARTITIONED mode could have any number of backups right? I want backups for high
availability and also my dataset is large. I guess I will use PARTITIONED mode and configure
number of backups based on actual needs in that case right?

From: user@ignite.apache.org 
Subject: Re: Is it possible to enable both REPLICATED and PARTITIONED?

Hi, Tracyl.

Actually, REPLICATED cache is a PARTITIONED cache win backups on all nodes.

But, why did you need  this?

On Mon, Oct 10, 2016 at 10:46 AM, Tracyl <tliang36@bloomberg.net> wrote:

As subject shows.


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-- 
Alexey Kuznetsov


-- 
Alexey Kuznetsov


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