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From Vladimir Rodionov <vrodio...@carrieriq.com>
Subject RE: Cache invalidation in Blockcache
Date Sun, 30 Mar 2014 20:29:34 GMT
The problem is how to determine "the latest version" w/o checking
memstore and all relevant HFile's. So , the answer is going to be - no.
You can not ask only MemStore and you can not rely on the fact
that MemStore always keeps the latest version of a rowkey.

HBase will pull all the versions of a rowkey from MemStore and HFile's, compare them
and only after then it will return the latest. This is why it is so important:

A. To have large block cache
B. To have working data set fit into this block cache.
C. To use Bloom filter's to avoid checking HFiles which do not contain versions of a requested

Best regards,
Vladimir Rodionov
Principal Platform Engineer
Carrier IQ, www.carrieriq.com
e-mail: vrodionov@carrieriq.com

From: chandra kant [chandralakshmikant90@gmail.com]
Sent: Sunday, March 30, 2014 12:12 AM
To: user@hbase.apache.org
Subject: Re: Cache invalidation in Blockcache

I am using habse 94 version . Just one clarification - if I am requesting
just a single row which is still in memstore , then read operation will
simply send back this result to client. This latest version of row won't be
cached in Blockcache. Blockcaching will only happen if data is read from
What if latest version of my row is in memstore and rest 2 versions are in
Hfile and I want all 3 versions? In this case, whether cached block with
that row key will be evicted from Blockcache?

On Sunday, 30 March 2014, Anoop John <anoop.hbase@gmail.com> wrote:

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