HBase - Column Database or Column Family Database ?

[#1]

Hi All,

I have some confusion about the physical storage structure of HBase . 

Is the HBase "Column Database" or "Column Family Database" ? 

For example, I have a table with tow column family in HBase .Columnfaily1 has three cols and columnfamily2 has two cols, and the data stored in the hbase table are a1 ~ f2. 

Which of the following answers can represent physical storage structure of HBase , the way of how data store in physical storeage ? And Why ?

Your prompt reply will be greatly appreciated !

Thanks

Pengcheng 

[#2]

> Is the HBase "Column Database" or "Column Family Database" ?

HBase uses column families as a separation unit when storing table data as flat files. The files however are also optimised for columnar reads, see HFile V2 section on http://blog.cloudera.com/blog/2012/06/hbase-io-hfile-input-output/

> Which of the following answers can represent physical storage structure of HBase , the way of how data store in physical storeage ?

It would roughly be (c), since the qualifiers are sorted too.

> And Why ?

See the blog link shared above, it details the architecture of the row storage format HBase uses.