Configure the Default Database for HBase Clients

For HBase version 1.1 and later, a default database configuration determines whether clients connect to HBase tables or HPE Ezmeral Data Fabric Database tables. You can change the default setting for all HBase clients, or you can set the database for a particular job. This setting is ignored for HBase 0.98.12 client connections.

Set the Default Database using configure.sh

configure.sh automatically sets the default database for a node based on the presence of the following mapr packages:

mapr-hbase-master
mapr-hbase-regionserver

configure.sh also provides a parameter that you can use to set the default database. To explicitly set the default database to either maprdb or hbase, run configure.sh with the -defaultdb parameter. For example:

configure.sh -R -defaultdb maprdb

The following table describes the effect of various configure.sh commands on the default database setting:

Table 1. Effect of Various `configure.sh` Commands on the Default Database
If ...	And you run `configure.sh` with the following `‑defaultdb` parameter ...
If ...	No `‑defaultdb` parameter specified	`‑defaultdb hbase`	`‑defaultdb maprdb`
`hbasemaster` or `hbaseregionserver` is installed on a node	The default database is set to `hbase`.	The default database is set to `hbase`	The default database is set to `hbase`, and the `maprdb` setting is ignored.
`hbasemaster` and `hbaseregionserver` are NOT installed on a node	The default database is set to `maprdb`.	The default database is set to `hbase`. However, this configuration does not work because HBase is not running.	The default database is set to `maprdb`.

For more information about configure.sh, see configure.sh.

Set the Default Database using hbase-site.xml

You can configure the mapr.hbase.default.db property in the hbase-site.xml to override the default database that is set for the cluster:

In the hbase-site.xml, edit the default value of mapr.hbase.default.db, and set it to either hbase or maprdb.
For example:
```
<property>
    <name>mapr.hbase.default.db</name>
    <value>hbase</value>
</property>
```
Copy the property to the hbase-site.xml on each node that runs HBase, including any HBase client nodes.

Set the Database Type in the Job Configuration

To set the database type in the job configuration you can add the following code:

To connect to HPE Ezmeral Data Fabric Database tables:

Configuration conf = HBaseConfiguration.create();
conf.set("mapr.hbase.default.db", "maprdb"); 
Connection connection = ConnectionFactory.createConnection(conf);
Table table = connection.getTable(<TABLE_NAME>);

To connect to HBase tables:

Configuration conf = HBaseConfiguration.create();
conf.set("mapr.hbase.default.db","hbase");
Connection connection = ConnectionFactory.createConnection(conf);
Table table = connection.getTable(<TABLE_NAME>);