HBase Datastores

DataNucleus supports persisting/retrieving objects to/from HBase datastore of Hadoop (using the datanucleus-hbase plugin). If you wish to help out development of this plugin either by contributing or by sponsoring particular functionality please contact us via the DataNucleus Forum.

Datastore Connection

The following persistence properties will connect to an HBase instance

datanucleus.ConnectionURL=hbase[:{server}:{port}]
datanucleus.ConnectionUserName=
datanucleus.ConnectionPassword=


If you just specify the URL as hbase then you have a local HBase datastore, otherwise it tries to connect to the datastore at {server}:{port} So you create your PersistenceManagerFactory or EntityManagerFactory with these properties. Thereafter you have the full power of the JDO or JPA APIs at your disposal, for your HBase datastore. Alternatively just put "hbase" as the URL and set the zookeeper details in "hbase-site.xml" as normal. If in doubt, refer to the HBase tutorial example for JDO.

Queries

Access Platform allows you to query the objects in the datastore using the following

  • JDOQL - language based around the objects that are persisted and using Java-type syntax
  • JPQL - language based around the objects that are persisted and using SQL-like syntax

Some components of a filter are handled in the datastore, and the remainder in-memory. Currently any expression of a field (in the same table), or a literal are handled in-datastore, as are the operators &&, ||, >, >=, <, <=, ==, and !=.