Configuring a Remote PostgreSQL Database for the Hive Metastore

Before you can run the Hive metastore with a remote PostgreSQL database, you must configure a JDBC driver to the remote PostgreSQL database, set up the initial database schema, and configure the PostgreSQL user account for the Hive user.

After installing PostgreSQL, perform the following steps to configure Hive Metastore on PostgreSQL.

Installing and Configuring PostgreSQL for the Hive Metastore

Download the PostgreSQL JDBC driver.
Refer to the official PostgreSQL JDBC Driver website to download the JDBC driver and get information about the latest updates. Determine the appropriate database version and get the released drivers and JAR file.
Run the following commands using sudo:
1. Move the JAR into the Java share directory:
```
sudo mv <postgresql-jdbc.jar> /usr/share/java/postgresql-jdbc.jar
```
2. Change the access mode of the JAR file to 644:
```
sudo chmod 644 /usr/share/java/postgresql-jdbc.jar
```
3. Create symbolic link to the /usr/lib/hive/lib/ directory, for example:
```
sudo ln -s /usr/share/java/postgresql-jdbc.jar /opt/mapr/hive/hive-<version>/lib/postgresql-jdbc.jar
```

Create the Metastore database and user accounts:

$ sudo -u postgres psql

postgres=# CREATE USER hiveuser WITH PASSWORD 'mypassword';
postgres=# CREATE DATABASE metastore;

To verify the connection from the Metastore service host, run the following command:

psql -h myhost -U hiveuser -d metastore
metastore=#

Configure the Metastore service to communicate with the PostgreSQL database by setting the necessary properties (shown below) in the /opt/mapr/hive//hive-<version>/conf/hive-site.xml file. Suppose a PostgreSQL database running on host myhost under the user account hive with the password mypassword, set the following configuration properties in the hive-site.xml file:
```
<property>
  <name>javax.jdo.option.ConnectionURL</name>
  <value>jdbc:postgresql://myhost/metastore</value>
</property>
 
<property>
  <name>javax.jdo.option.ConnectionDriverName</name>
  <value>org.postgresql.Driver</value>
</property>
 
<property>
  <name>javax.jdo.option.ConnectionUserName</name>
  <value>hiveuser</value>
</property>
 
<property>
  <name>javax.jdo.option.ConnectionPassword</name>
  <value>mypassword</value>
</property>

<property>
  <name>hive.metastore.uris</name>
  <value>thrift://<n.n.n.n>:9083</value>
  <description>IP address (or fully-qualified domain name) and port of the metastore host</description>
  </property>
```
NOTE Though you can use the same hive-site.xml properties on all the hosts (client, metastore, HiveServer), hive.metastore.uris is the only property that must be configured on all of the hosts; the other properties are only needed on the Metastore host.

Run schemaTool to create the initial DB structure:

/opt/mapr/hive/hive-<version>/bin/schematool -dbType postgres -initSchema