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: jdcry...@gmail.com [mailto:jdcry...@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 > <hvash...@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 > >
