On Tue, Apr 6, 2010 at 7:14 AM, 赵辉 <hzhao2...@gmail.com> wrote: > hi, i am interested in HBASE and have viewed lots of materials about it, > but now i have some questions! > The first question is about the data layout and its index,maybe you can tell > me about the difference on Mfile,Hfile and Tfile.
Never heard of Mfile. HFile is a specialized TFile for HBase. Is there anything in particular you need to know about? > The second is about the caches(both metadata cache and data cache),i want > to know if there are ,where they locate in and how they work. Like Bigtable there's a .META. cache which works like a big map in the client and a block cache in the region servers which works like a LRU. > The third is about the hbase shell, which implements an alter command, > that can change or add or delete a column family,but i remember the column > family cannot be changed after the table is created. I also want to know > default max VERSIONs, when i create a table i give the VERSION 2,later i put > three values for the same row+column and different timestamp, but i can get > values rather than only two. The column family can be changed, not sure what you are referring to. Default max versions is 3, the rest of the question is unintelligible. > I wish your detail answers, thanks! >
