Hbase/HbaseArchitecture - Hadoop Wiki

Hbase/HbaseArchitecture - Hadoop Wiki: "HBase uses a data model very similar to that of Bigtable. Users store data rows in labelled tables. A data row has a sortable key and an arbitrary number of columns. The table is stored sparsely, so that rows in the same table can have crazily-varying columns, if the user likes.

A column name has the form ':' where and can be any string you like. A single table enforces its set of s (called 'column families'). You can only adjust this set of families by performing administrative operations on the table. However, you can use new strings at any write without preannouncing it. HBase stores column families physically close on disk. So the items in a given column family should have roughly the same write/read behavior.

Writes are row-locked only. You cannot lock multiple rows at once. All row-writes are atomic by default.

All updates to the database have an associated timestamp. The HBase will store a configurable number of versions of a given cell. Clients can get data by asking for the 'most recent value as of a certain time'. Or, clients can fetch all available versions at once."