Hi Lars, What do you mean a set of "keys that have the same row key" and "colocated"? It will be appreciated if you could show an example or provide more information.
regards, Lin On Mon, Aug 6, 2012 at 3:42 AM, lars hofhansl <lhofha...@yahoo.com> wrote: > Hi Lin, > > HBase stores key -> value mappings sorted by key. So it is a key value > store. > > The key has internal structure, for example it starts with a row key. > HBase makes extra guarantees about a set of keys that have the same row > key (keeps them colocated, allows atomic operations, etc). > > I tried to write this up a while back: > http://hadoop-hbase.blogspot.com/2011/12/introduction-to-hbase.html > > -- Lars > > > > ----- Original Message ----- > From: Lin Ma <lin...@gmail.com> > To: user@hbase.apache.org > Cc: > Sent: Sunday, August 5, 2012 6:04 AM > Subject: column based or row based storage for HBase? > > Hi guys, > > I am wondering whether HBase is using column based storage or row based > storage? > > - I read some technical documents and mentioned advantages of HBase is > using column based storage to store similar data together to foster > compression. So it means same columns of different rows are stored > together; > - But I also learned HBase is a sorted key-value map in underlying > HFile. It uses key to address all related columns for that key (row), > so it > seems to be a row based storage? > > It is appreciated if anyone could clarify my confusions. Any related > documents or code for more details are welcome. > > thanks in advance, > > Lin > >
