Configuring the database

An overview about how to configure relational databases

This guide explains how to configure the Keycloak server to store data in a relational database.

Supported databases

The server has built-in support for different databases. You can query the available databases by viewing the expected values for the db configuration option. The following table lists the supported databases and their tested versions.

Database Option value Tested Version

MariaDB Server



Microsoft SQL Server






Oracle Database






Amazon Aurora PostgreSQL



By default, the server uses the dev-file database. This is the default database that the server will use to persist data and only exists for development use-cases. The dev-file database is not suitable for production use-cases, and must be replaced before deploying to production.

Configuring a database

For each supported database, the server provides some opinionated defaults to simplify database configuration. You complete the configuration by providing some key settings such as the database host and credentials.

  1. Start the server and set the basic options to configure a database

    bin/kc.[sh|bat] start --db postgres --db-url-host mypostgres --db-username myuser --db-password change_me

    This command includes the minimum settings needed to connect to the database.

The default schema is keycloak, but you can change it by using the db-schema configuration option.

Do NOT use the --optimized flag for the start command if you want to use a particular DB (except the H2). Executing the build phase before starting the server instance is necessary. You can achieve it either by starting the instance without the --optimized flag, or by executing the build command before the optimized start. For more information, see Configuring Keycloak.

Overriding default connection settings

The server uses JDBC as the underlying technology to communicate with the database. If the default connection settings are insufficient, you can specify a JDBC URL using the db-url configuration option.

The following is a sample command for a PostgreSQL database.

bin/kc.[sh|bat] start --db postgres --db-url jdbc:postgresql://mypostgres/mydatabase

Be aware that you need to escape characters when invoking commands containing special shell characters such as ; using the CLI, so you might want to set it in the configuration file instead.

Overriding the default JDBC driver

The server uses a default JDBC driver accordingly to the database you chose.

To set a different driver you can set the db-driver with the fully qualified class name of the JDBC driver:

bin/kc.[sh|bat] start --db postgres --db-driver=my.Driver

Regardless of the driver you set, the default driver is always available at runtime.

Only set this property if you really need to. For instance, when leveraging the capabilities from a JDBC Driver Wrapper for a specific cloud database service.

Configuring Unicode support for the database

Unicode support for all fields depends on whether the database allows VARCHAR and CHAR fields to use the Unicode character set.

  • If these fields can be set, Unicode is likely to work, usually at the expense of field length.

  • If the database only supports Unicode in the NVARCHAR and NCHAR fields, Unicode support for all text fields is unlikely to work because the server schema uses VARCHAR and CHAR fields extensively.

The database schema provides support for Unicode strings only for the following special fields:

  • Realms: display name, HTML display name, localization texts (keys and values)

  • Federation Providers: display name

  • Users: username, given name, last name, attribute names and values

  • Groups: name, attribute names and values

  • Roles: name

  • Descriptions of objects

Otherwise, characters are limited to those contained in database encoding, which is often 8-bit. However, for some database systems, you can enable UTF-8 encoding of Unicode characters and use the full Unicode character set in all text fields. For a given database, this choice might result in a shorter maximum string length than the maximum string length supported by 8-bit encodings.

Configuring Unicode support for an Oracle database

Unicode characters are supported in an Oracle database if the database was created with Unicode support in the VARCHAR and CHAR fields. For example, you configured AL32UTF8 as the database character set. In this case, the JDBC driver requires no special settings.

If the database was not created with Unicode support, you need to configure the JDBC driver to support Unicode characters in the special fields. You configure two properties. Note that you can configure these properties as system properties or as connection properties.

  1. Set oracle.jdbc.defaultNChar to true.

  2. Optionally, set oracle.jdbc.convertNcharLiterals to true.

    For details on these properties and any performance implications, see the Oracle JDBC driver configuration documentation.

Unicode support for a Microsoft SQL Server database

Unicode characters are supported only for the special fields for a Microsoft SQL Server database. The database requires no special settings.

The sendStringParametersAsUnicode property of JDBC driver should be set to false to significantly improve performance. Without this parameter, the Microsoft SQL Server might be unable to use indexes.

Configuring Unicode support for a MySQL database

Unicode characters are supported in a MySQL database if the database was created with Unicode support in the VARCHAR and CHAR fields when using the CREATE DATABASE command.

Note that the utf8mb4 character set is not supported due to different storage requirements for the utf8 character set. See MySQL documentation for details. In that situation, the length restriction on non-special fields does not apply because columns are created to accommodate the number of characters, not bytes. If the database default character set does not allow Unicode storage, only the special fields allow storing Unicode values.

  1. Start MySQL Server.

  2. Under JDBC driver settings, locate the JDBC connection settings.

  3. Add this connection property: characterEncoding=UTF-8

Configuring Unicode support for a PostgreSQL database

Unicode is supported for a PostgreSQL database when the database character set is UTF8. Unicode characters can be used in any field with no reduction of field length for non-special fields. The JDBC driver requires no special settings. The character set is determined when the PostgreSQL database is created.

  1. Check the default character set for a PostgreSQL cluster by entering the following SQL command.

    show server_encoding;
  2. If the default character set is not UTF 8, create the database with the UTF8 as the default character set using a command such as:

    create database keycloak with encoding 'UTF8';

Preparing for Amazon Aurora PostgreSQL

When using Amazon Aurora PostgreSQL, the Amazon Web Services JDBC Driver offers additional features like transfer of database connections when a writer instance changes in a Multi-AZ setup. This driver is not part of the distribution and needs to be installed before it can be used.

To install this driver, apply the following steps:

  1. When running the unzipped distribution: Download the JAR file from the Amazon Web Services JDBC Driver releases page and place it in Keycloak’s providers folder.

  2. When running containers: Build a custom Keycloak image and add the JAR in the providers folder.

    A minimal Dockerfile to build an image which can be used with the Keycloak Operator looks like the following:

    ADD --chmod=0666 /opt/keycloak/providers/aws-advanced-jdbc-wrapper.jar

    See the Running Keycloak in a container guide for details on how to build optimized images, and the Using custom Keycloak images guide on how to run optimized and non-optimized images with the Keycloak Operator.

  3. Configure Keycloak to run with the following parameters:


    Insert aws-wrapper to the regular PostgreSQL JDBC URL resulting in a URL like jdbc:aws-wrapper:postgresql://....


    Set to to use the AWS JDBC wrapper.


    Set to false, as the Amazon Web Services JDBC Driver does not support XA transactions.

Preparing for MySQL server

Beginning with MySQL 8.0.30, MySQL supports generated invisible primary keys for any InnoDB table that is created without an explicit primary key (more information here). If this feature is enabled, the database schema initialization and also migrations will fail with the error message Multiple primary key defined (1068). You then need to disable it by setting the parameter sql_generate_invisible_primary_key to OFF in your MySQL server configuration before installing or upgrading Keycloak.

Changing database locking timeout in a cluster configuration

Because cluster nodes can boot concurrently, they take extra time for database actions. For example, a booting server instance may perform some database migration, importing, or first time initializations. A database lock prevents start actions from conflicting with each other when cluster nodes boot up concurrently.

The maximum timeout for this lock is 900 seconds. If a node waits on this lock for more than the timeout, the boot fails. The need to change the default value is unlikely, but you can change it by entering this command:

bin/kc.[sh|bat] start --spi-dblock-jpa-lock-wait-timeout 900

Using Database Vendors without XA transaction support

Keycloak uses XA transactions and the appropriate database drivers by default. Certain vendors, such as Azure SQL and MariaDB Galera, do not support or rely on the XA transaction mechanism. To use Keycloak without XA transaction support using the appropriate JDBC driver, enter the following command:

bin/kc.[sh|bat] build --db=<vendor> --transaction-xa-enabled=false

Keycloak automatically chooses the appropriate JDBC driver for your vendor.

Setting JPA provider configuration option for migrationStrategy

To setup the JPA migrationStrategy (manual/update/validate) you should setup JPA provider as follows:

Setting the migration-strategy for the quarkus provider of the connections-jpa SPI
bin/kc.[sh|bat] start --spi-connections-jpa-quarkus-migration-strategy=manual

If you want to get a SQL file for DB initialization, too, you have to add this additional SPI initializeEmpty (true/false):

Setting the initialize-empty for the quarkus provider of the connections-jpa SPI
bin/kc.[sh|bat] start --spi-connections-jpa-quarkus-initialize-empty=false

In the same way the migrationExport to point to a specific file and location:

Setting the migration-export for the quarkus provider of the connections-jpa SPI
bin/kc.[sh|bat] start --spi-connections-jpa-quarkus-migration-export=<path>/<file.sql>

Relevant options



The database vendor.

CLI: --db
Env: KC_DB

dev-file (default), dev-mem, mariadb, mssql, mysql, oracle, postgres


The fully qualified class name of the JDBC driver.

If not set, a default driver is set accordingly to the chosen database.

CLI: --db-driver


The password of the database user.

CLI: --db-password


The initial size of the connection pool.

CLI: --db-pool-initial-size


The maximum size of the connection pool.

CLI: --db-pool-max-size

100 (default)


The minimal size of the connection pool.

CLI: --db-pool-min-size


The database schema to be used.

CLI: --db-schema


The full database JDBC URL.

If not provided, a default URL is set based on the selected database vendor. For instance, if using postgres, the default JDBC URL would be jdbc:postgresql://localhost/keycloak.

CLI: --db-url


Sets the database name of the default JDBC URL of the chosen vendor.

If the db-url option is set, this option is ignored.

CLI: --db-url-database


Sets the hostname of the default JDBC URL of the chosen vendor.

If the db-url option is set, this option is ignored.

CLI: --db-url-host


Sets the port of the default JDBC URL of the chosen vendor.

If the db-url option is set, this option is ignored.

CLI: --db-url-port


Sets the properties of the default JDBC URL of the chosen vendor.

Make sure to set the properties accordingly to the format expected by the database vendor, as well as appending the right character at the beginning of this property value. If the db-url option is set, this option is ignored.

CLI: --db-url-properties


The username of the database user.

CLI: --db-username


If set to false, Keycloak uses a non-XA datasource in case the database does not support XA transactions.

CLI: --transaction-xa-enabled

true (default), false

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