Glossary

Table

HBase Table is three dimensional sorted map. It maps from Cartesian product of row key, column key and timestamp to cell value:

(row:byte[] x column:byte[] x timestamp:Long) -> byte[]

All HBase data is stored in cell of tables.

Row

One of HBase Table dimensions. I has Row Key that is arbitrary array of bytes. Table is sorted in lexicographical order by it's Row Key.

Column

One of HBase Table dimensions. A column name has the form "<family>:<label>" where <family> and <label> can be arbitrary byte arrays. A table enforces its set of <family>s (called "column families").

Column Family

Column family is a predefined arbitrary set of columns and stored in HBase Schema. To create some column in family you should create family first. A column family regroups data of a same nature in HBase and has no constraint on the type. For each Row data in one Column family is physically stored at one server. Each Column family has is attributes like: Compression, Timestamps, Block Cache and etc.

Timestamps