---

id: mysql title: “MySQL metadata store”

To use this Apache Druid extension, include mysql-metadata-storage in the extensions load list.

With the MySQL extension, you can use MySQL as a metadata store or ingest from a MySQL database.

The extension requires a connector library that's not included with Druid. See the Prerequisites for installation instructions.

Prerequisites

To use the MySQL extension, you need to install one of the following libraries:

• MySQL Connector/J
• MariaDB Connector/J

Install MySQL Connector/J

The MySQL extension uses Oracle's MySQL JDBC driver. The current version of Druid uses version 8.2.0. Other versions may not work with this extension.

You can download the library from one of the following sources:

• MySQL website
  Visit the archives page to access older product versions.
• Maven Central (direct download)
• Your package manager. For example, libmysql-java on APT for a Debian-based OS.

The download includes the MySQL connector JAR file with a name like mysql-connector-j-8.2.0.jar. Copy or create a symbolic link to this file inside the lib folder in the distribution root directory.

Install MariaDB Connector/J

This extension also supports using the MariaDB connector jar. The current version of Druid uses version 2.7.3. Other versions may not work with this extension.

You can download the library from one of the following sources:

• MariaDB website
  Click Show All Files to access older product versions.
• Maven Central (direct download)

The download includes the MariaDB connector JAR file with a name like maria-java-client-2.7.3.jar. Copy or create a symbolic link to this file inside the lib folder in the distribution root directory.

To configure the mysql-metadata-storage extension to use the MariaDB connector library instead of MySQL, set druid.metadata.mysql.driver.driverClassName=org.mariadb.jdbc.Driver.

The protocol of the connection string is jdbc:mysql: or jdbc:mariadb:, depending on your specific version of the MariaDB client library. For more information on the parameters to configure a connection, see the MariaDB documentation for your connector version.

Set up MySQL

To avoid issues with upgrades that require schema changes to a large metadata table, consider a MySQL version that supports instant ADD COLUMN semantics. For example, MySQL 8.

1. Install MySQL

Use your favorite package manager to install mysql, e.g.:

• on Ubuntu/Debian using apt apt-get install mysql-server
• on OS X, using Homebrew brew install mysql

Alternatively, download and follow installation instructions for MySQL Community Server here: http://dev.mysql.com/downloads/mysql/.

This extension also supports using MariaDB server, https://mariadb.org/download/, substituting for MariaDB in the following instructions where appropriate.

2. Create a druid database and user

Connect to MySQL from the machine where it is installed.

mysql -u root

Paste the following snippet into the mysql prompt:

-- create a druid database, make sure to use utf8mb4 as encoding
CREATE DATABASE druid DEFAULT CHARACTER SET utf8mb4;

-- create a druid user
CREATE USER 'druid'@'localhost' IDENTIFIED BY 'password';

-- grant the user all the permissions on the database we just created
GRANT ALL PRIVILEGES ON druid.* TO 'druid'@'localhost';

3. Configure your Druid metadata storage extension:

Add the following parameters to your Druid configuration, replacing <host> with the location (host name and port) of the database.

druid.extensions.loadList=["mysql-metadata-storage"]
druid.metadata.storage.type=mysql
druid.metadata.storage.connector.connectURI=jdbc:mysql://<host>/druid
druid.metadata.storage.connector.user=druid
druid.metadata.storage.connector.password=diurd

If using the MariaDB connector library, set druid.metadata.mysql.driver.driverClassName=org.mariadb.jdbc.Driver.

Encrypt MySQL connections

This extension provides support for encrypting MySQL connections. To get more information about encrypting MySQL connections using TLS/SSL in general, please refer to this guide.

Configuration properties

Property	Description	Default	Required
druid.metadata.mysql.ssl.useSSL	Enable SSL	false	no
druid.metadata.mysql.ssl.clientCertificateKeyStoreUrl	The file path URL to the client certificate key store.	none	no
druid.metadata.mysql.ssl.clientCertificateKeyStoreType	The type of the key store where the client certificate is stored.	none	no
druid.metadata.mysql.ssl.clientCertificateKeyStorePassword	The Password Provider or String password for the client key store.	none	no
druid.metadata.mysql.ssl.verifyServerCertificate	Enables server certificate verification.	false	no
druid.metadata.mysql.ssl.trustCertificateKeyStoreUrl	The file path to the trusted root certificate key store.	Default trust store provided by MySQL	yes if verifyServerCertificate is set to true and a custom trust store is used
druid.metadata.mysql.ssl.trustCertificateKeyStoreType	The type of the key store where trusted root certificates are stored.	JKS	yes if verifyServerCertificate is set to true and keystore type is not JKS
druid.metadata.mysql.ssl.trustCertificateKeyStorePassword	The Password Provider or String password for the trust store.	none	yes if verifyServerCertificate is set to true and password is not null
druid.metadata.mysql.ssl.enabledSSLCipherSuites	Overrides the existing cipher suites with these cipher suites.	none	no
druid.metadata.mysql.ssl.enabledTLSProtocols	Overrides the TLS protocols with these protocols.	none	no

MySQL input source

The MySQL extension provides an implementation of an SQL input source to ingest data into Druid from a MySQL database. For more information on the input source parameters, see SQL input source.

{
  "type": "index_parallel",
  "spec": {
    "dataSchema": {
      "dataSource": "some_datasource",
      "dimensionsSpec": {
        "dimensionExclusions": [],
        "dimensions": [
          "dim1",
          "dim2",
          "dim3"
        ]
      },
      "timestampSpec": {
        "format": "auto",
        "column": "ts"
      },
      "metricsSpec": [],
      "granularitySpec": {
        "type": "uniform",
        "segmentGranularity": "DAY",
        "queryGranularity": {
          "type": "none"
        },
        "rollup": false,
        "intervals": null
      },
      "transformSpec": {
        "filter": null,
        "transforms": []
      }
    },
    "ioConfig": {
      "type": "index_parallel",
      "inputSource": {
        "type": "sql",
        "database": {
          "type": "mysql",
          "connectorConfig": {
            "connectURI": "jdbc:mysql://some-rds-host.us-west-1.rds.amazonaws.com:3306/druid",
            "user": "admin",
            "password": "secret"
          }
        },
        "sqls": [
          "SELECT * FROM some_table"
        ]
      },
      "inputFormat": {
        "type": "json"
      }
    },
    "tuningConfig": {
      "type": "index_parallel"
    }
  }
}