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From Jean-Daniel Cryans <jdcry...@apache.org>
Subject Re: hfile - Storefile
Date Wed, 01 Sep 2010 20:04:11 GMT
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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