Thanks Ted & Mikael. Thanks & Regards, B Anil Kumar.
On Mon, Dec 9, 2013 at 6:38 PM, Mikael Sitruk <[email protected]>wrote: > LSM tree are the basis for reducing random I/O which is a huge performance > factor with big data system. A good overview can be found in HBase in > action book, from Lars George. > The basic idea is that you have an in memory structure for the latest > changes and a structure stored on files, The files content is always > ordered by key, and each row the file is jus the row_key, Column family > identifier, column name, timestamp and the value (+ a marker). > When the memory is full, the memory structure is flushed to disk, when > there are a certain amount of files on filesystem the files are merged to > bigger ones, since the files are ordered the merge is very fast, (like > merge in mergesort algo) > > > On Sun, Dec 8, 2013 at 8:42 AM, Ted Yu <[email protected]> wrote: > > > Searching for 'lsm tree hbase' would give you several articles. > > > > I am in China - the search results are mostly in Chinese. > > > > You should be able to read this: > > > > > http://stackoverflow.com/questions/13762992/log-structured-merge-tree-in-hbase > > > > Cheers > > > > > > On Wed, Dec 4, 2013 at 6:49 PM, AnilKumar B <[email protected]> > wrote: > > > > > Hi, > > > > > > We are trying to understand how and where exactly LSM tress are used in > > > HBase. Currently as per our understanding, while flushing memstore to > > Store > > > files and while HFile compaction it is used. And sits on top of HFiles > at > > > memstore level. > > > > > > Is this understanding correct. Can you please give more insight on > this? > > > How exactly is the merging done? > > > > > > Thanks & Regards, > > > B Anil Kumar. > > > > > >
