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Date: Mon, 17 Mar 2014 09:02:54 -0700
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 <CALte62xLA_o9Nxv42NPbYouN8Z=UdVi+S1U5z+Kk7pR0q3A_vA@mail.gmail.com>
Subject: Re: block cache size questions
From: Ted Yu <yuzhihong@gmail.com>
To: "user@hbase.apache.org" <user@hbase.apache.org>
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For #1, see
http://stackoverflow.com/questions/4667483/how-is-the-default-java-heap-size-determined

For #3, it is currently not possible.

Cheers


On Mon, Mar 17, 2014 at 6:01 AM, Linlin Du <linlindu2009@hotmail.com> wrote:

> Hi all,
>
> First question:
> According to documentation, hfile.block.cache.size is by default 40
> percentage of maximum heap (-Xmx setting). If -Xmx is not used and only
> -Xms is used, what will it be in this case?
>
> Second question:
> This 40% heap space is shared by all entities (stores). How much block
> cache is used by each store (entity)? Is it allocated on demand? If a
> region has never been read after the region server is up, will block cache
> be allocated for it?
>
> Third question:
> Is it possible to tell from .META when a region was last read? If so, how?
>
> Many thanks,
>
> Linlin
>
>
>
>
>

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