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From Doug Meil <doug.m...@explorysmedical.com>
Subject Re: Hbase -question
Date Tue, 15 Nov 2011 13:23:01 GMT

Hi there-

You probably want to read these two entries in the book...

http://hbase.apache.org/book.html#store
http://hbase.apache.org/book.html#wal




On 11/15/11 2:00 AM, "Aditya Kumar" <adityakumar345@yahoo.com> wrote:

>Thanks for the reply and explanation.
>
>Can you explain me the following:
>HFile is having the raw data blocks and also the indices to find the the
>blocks  about the file.
>i.e, It has the raw data blocks and indices of these blocks?
>
>will it not be heavy to have multiple copies?
>I was of the understanding that : Hfile will have only the filename with
>the indices of the blocks.
>
>can you please clarify me more in detail why we need to have the raw data
>also?
>
>
>
>
>________________________________
>From: Stack <stack@duboce.net>
>To: dev@hbase.apache.org; Aditya Kumar <adityakumar345@yahoo.com>
>Sent: Monday, November 14, 2011 10:37 PM
>Subject: Re: Hbase -question
>
>On Mon, Nov 14, 2011 at 10:25 PM, Aditya Kumar <adityakumar345@yahoo.com>
>wrote:
>> can any one please clarify me :
>> what is HLog,storefile.Hfile and store?
>
>HLog is the name of our WAL implementation (see in code the wal
>package, see how the WAL implementation is done in the HLog class).
>
>HFile is about raw data blocks and indices to find those blocks as
>well as metadata about the file.  Ideally it knows nothing about the
>upper hbase tiers.  StoreFile then is the glue between hbase and its
>raw storage HFile.
>
>Store is the implementation of a Column Family (The Store class should
>have been called ColumnFamily)
>
>Sorry our naming is a little less clear than it should be.
>
>St.Ack



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