hbase-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Jonathan Gray <jg...@facebook.com>
Subject RE: hfile - Storefile
Date Wed, 01 Sep 2010 22:04:11 GMT
Himanshu,

Don't be afraid to check-out the HBase codebase from SVN and scope out HFile and StoreFile
classes for yourself!

HBase has a fairly easy to follow codebase despite being rather large.

JG

> -----Original Message-----
> From: jdcryans@gmail.com [mailto:jdcryans@gmail.com] On Behalf Of Jean-
> Daniel Cryans
> Sent: Wednesday, September 01, 2010 1:04 PM
> To: dev@hbase.apache.org
> Subject: Re: hfile - Storefile
> 
> 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
> >

Mime
View raw message