6. [Optional] Install a Metastore Database

If you are installing Hive and HCatalog or installing Oozie, you must install a database to store metadata information in the metastore. You can either use an existing database instance or install a new instance manually. HDP supports the following databases for the metastore:

Postgres 8.x, 9.x
MySQL 5.x
Oracle 11g r2
SQL Server 2012, 2014

	Note
	By default, Hive uses the Derby database for the metastore. However, Derby is not supported for production systems.

The following instructions explain how to install MySQL as the metastore. See your third-party documentation for instructions on how to install other supported databases.

To install a new instance of MySQL:

Connect to the host machine you plan to use for Hive and HCatalog.
Install MySQL server. From a terminal window, type:
For RHEL/CentOS:
```
yum install mysql-server
```
Start the instance.
```
/etc/init.d/mysqld start
```

Set the root user password.

mysqladmin -u root -p‘{password}’ password $mysqlpassword

Remove unnecessary information from log and STDOUT.
```
mysqladmin -u root 2>&1 >/dev/null
```

As root, use mysql (or other client tool) to create the “dbuser” and grant it adequate privileges. This user provides access to the Hive metastore.

CREATE USER '$dbusername'@'localhost' IDENTIFIED BY '$dbuserpassword';
GRANT ALL PRIVILEGES ON *.* TO 'dbuser'@'localhost';
CREATE USER 'dbuser'@'%' IDENTIFIED BY 'dbuserpassword';
GRANT ALL PRIVILEGES ON *.* TO 'dbuser'@'%';
FLUSH PRIVILEGES;
mysql> GRANT ALL PRIVILEGES ON *.* TO 'dbuser'@'localhost' WITH GRANT OPTION;
Query OK, 0 rows affected (0.00 sec)
mysql> GRANT ALL PRIVILEGES ON *.* TO 'dbuser'@'%' WITH GRANT OPTION;
Query OK, 0 rows affected (0.00 sec)

See if you can connect to the database as that user. You are prompted to enter the $dbuserpassword password above.
```
mysql -u dbuser -p$dbuserpassword
```
Install the MySQL connector JAR file.
- For RHEL/CentOS/Oracle Linux:
```
yum install mysql-connector-java*
```
- For SLES:
```
zypper install mysql-connector-java*
```

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