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From Andrew Purtell <apurt...@apache.org>
Subject Re: IN_MEMORY setting
Date Sat, 09 Jul 2011 01:40:44 GMT
IN_MEMORY means that HBase will try really hard to keep all of the data blocks for a table
in the block cache. Block cache is expired on a LRU basis in three priority bands. Blocks
for IN_MEMORY tables have the highest priority. They will be the last to be evicted.

It does not mean data is never written to disk -- all data in HBase is backed by files in
HDFS.

It does not mean the table data won't be evicted if the table becomes very large and it cannot
all fit in the available configured block cache.

Best regards,


   - Andy

Problems worthy of attack prove their worth by hitting back. - Piet Hein (via Tom White)


----- Original Message -----
> From: Weiwei Xiong <xiongww@gmail.com>
> To: user@hbase.apache.org
> Cc: 
> Sent: Friday, July 8, 2011 6:04 PM
> Subject: IN_MEMORY setting
> 
> Hi all,
> 
> Is there anyway to always keep a table in memory? Will IN_MEMORY setting
> server this purpose?
> 
> Thanks,
> ww
>

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