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From Stack <st...@duboce.net>
Subject Re: hfile - Storefile
Date Wed, 01 Sep 2010 21:42:55 GMT
This is my fault.  I'm moderator on the list.  Some stuff goes to
moderator first and I'm not fast enough clearing them.  Sorry about
that J-D and Himanshu.
St.Ack

On Wed, Sep 1, 2010 at 1:07 PM, Himanshu Vashishtha
<vashishtha.h@gmail.com> wrote:
> yeah! it got posted twice, unintentionally. Thanks for the answer, J-D.
>
> On Wed, Sep 1, 2010 at 2:04 PM, Jean-Daniel Cryans <jdcryans@apache.org>wrote:
>
>> Like I answered this morning to the same question:
>>
>> StoreFile is just a wrapper for HFile to add HBase-sugar on top of it.
>>
>> J-D
>>
>> On Wed, Sep 1, 2010 at 7:59 AM, Himanshu Vashishtha
>> <hvashish@cs.ualberta.ca> wrote:
>> > It will be great if anyone can point out the difference in their
>> > functionality. What I understand is Storefile is made persistent in fs,
>> > compactions occurred on these (to me, its an equivalent of SSTable).
>> > Hfile is derived (evolved) from MapFile, giving access to faster random
>> > reads (as it uses index to look for a key etc). Is it a handler sort of
>> to
>> > access the persisted Storefile? By their package structure, i think so
>> > (Hfile is in io, storefile is in rs).
>> >
>> > Now, the interesting thing is I know I am possibly wrong. As Ryan pointed
>> > out recently:"Hfiles are write once read many. Once written they cannot
>> be
>> > modified so there is way to move things around."...
>> > This is a SSTable property: they are immutable. And they are merged into
>> one
>> > by compactions (major).
>> >
>> > I will appreciate if you can provide the missing link.
>> >
>> > Thanks,
>> > ~Himanshu
>> >
>>
>

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