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HBase, mail # dev - hfile - Storefile


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Re: hfile - Storefile
Himanshu Vashishtha 2010-09-01, 20:07
yeah! it got posted twice, unintentionally. Thanks for the answer, J-D.

On Wed, Sep 1, 2010 at 2:04 PM, Jean-Daniel Cryans <[EMAIL PROTECTED]>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
> <[EMAIL PROTECTED]> 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
> >
>