Quarkus - Datasources

    The main way of obtaining connections to a database is to use a datasource and configure a JDBC driver.

    In Quarkus, the preferred datasource and connection pooling implementation is Agroal.

    Agroal is a modern, light weight connection pool implementation designed for very high performance and scalability,and features first class integration with the other components in Quarkus, such as security, transaction management components, health metrics.

    This guide will explain how to:

    • configure a datasource, or multiple datasources

    • how to obtain a reference to those datasources in code

    • which pool tuning configuration properties are available

    To complete this guide, you will need:

    • less than 10 minutes

    • an IDE

    • JDK 1.8+ installed with configured appropriately

    • Apache Maven 3.5.3+

    Creating the Maven project

    First, we need a new project. Create a new project with the following command:

    This will generate:

    • the Maven structure

    • a landing page accessible on http://localhost:8080

    • an example Dockerfile files for both native and jvm modes

    • an org.acme.datasource.GreetingResource resource

    • an example integration test

    Adding maven dependencies

    Next, you will need to add the quarkus-agroal dependency to your project.

    You can add it using a simple Maven command:

    1. ./mvnw quarkus:add-extension -Dextensions="agroal"

    You will also need to choose, and add, the Quarkus extension for your relational database driver.

    Quarkus provides driver extensions for:

    • PostgreSQL - jdbc-postgresql

    • MariaDB - jdbc-mariadb

    • MySQL - jdbc-mysql

    • Microsoft SQL Server - jdbc-mssql

    • Derby - jdbc-derby

    As usual, you can install the extension using add-extension.

    To install the PostgreSQL driver dependency for instance, just run the following command:

    1. ./mvnw quarkus:add-extension -Dextensions="jdbc-postgresql"

    Once the dependencies are added to your pom.xml file, you’ll need to configure Agroal.

    This is done in the src/main/resources/application.properties file.

    A viable configuration file would be:

    There are other configuration options, detailed below.

    Each of the supported databases contains different JDBC URL configuration options.Going into each of those options is beyond the scope of this document, but it gives an overview of each database URL and link to the official documentation.

    H2

    jdbc:h2:{ {.|mem:}[name] | [file:]fileName | {tcp|ssl}:[//]server[:port][,server2[:port]]/name }[;key=value…​]

    • Example
    • jdbc:h2:tcp://localhost/~/test, jdbc:h2:mem:myDB

    H2 is an embedded database.It can run as a server, based on a file, or live completely in memory.All of these options are available as listed above.You can find more information at the .

    PostgreSQL

    PostgreSQL only runs as a server, as do the rest of the databases below.As such, you must specify connection details, or use the defaults.

    jdbc:postgresql:[//][host][:port][/database][?key=value…​]

    • Example
    • jdbc:postgresql://localhost/test

    Defaults for the different parts are as follows:

    • host

    • localhost

    • port

    • 5432

    • database

    • same name as the username

    The go into more detail and list optional parameters as well.

    MariaDB

    jdbc:mariadb:[replication:|failover:|sequential:|aurora:]//<hostDescription>[,<hostDescription>…​]/[database][?<key1>=<value1>[&<key2>=<value2>]] hostDescription:: <host>[:<portnumber>] or address=(host=<host>)[(port=<portnumber>)][(type=(master|slave))]

    • Example
    • jdbc:mariadb://localhost:3306/test

    You can find more information about this feature and others detailed in the .

    MySQL

    • Example
    • jdbc:mysql://localhost:3306/test

    You can find more information about this feature and others detailed in the .

    Microsoft SQL Server

    Microsoft SQL Server takes a connection URL in the following form:

    jdbc:sqlserver://[serverName[\instanceName][:portNumber]][;property=value[;property=value]]

    • Example
    • jdbc:sqlserver://localhost:1433;databaseName=AdventureWorks

    The Microsoft SQL Server JDBC driver works essentially the same as the others.More details can be found in the .

    Derby

    jdbc:derby:[//serverName[:portNumber]/][memory:]databaseName[;property=value[;property=value]]

    • Example
    • jdbc:derby://localhost:1527/myDB, jdbc:derby:memory:myDB;create=true

    Derby is an embedded database.It can run as a server, based on a file, or live completely in memory.All of these options are available as listed above.You can find more information at the .

    Injecting a Datasource

    Because Quarkus uses CDI, injecting a datasource is very simple:

    1. AgroalDataSource defaultDataSource;

    In the above example, the type is AgroalDataSource which is a subtype of javax.sql.DataSource.Because of this, you can also use javax.sql.DataSource.

    Multiple Datasources

    Agroal allows you to configure multiple datasources.It works exactly the same way as a single datasource, with one important change: a name.

    1. quarkus.datasource.driver=org.h2.Driver
    2. quarkus.datasource.url=jdbc:h2:tcp://localhost/mem:default
    3. quarkus.datasource.username=username-default
    4. quarkus.datasource.min-size=3
    5. quarkus.datasource.max-size=13
    7. quarkus.datasource.users.driver=org.h2.Driver
    8. quarkus.datasource.users.url=jdbc:h2:tcp://localhost/mem:users
    9. quarkus.datasource.users.username=username1
    10. quarkus.datasource.users.min-size=1
    11. quarkus.datasource.users.max-size=11
    13. quarkus.datasource.inventory.driver=org.h2.Driver
    14. quarkus.datasource.inventory.url=jdbc:h2:tcp://localhost/mem:inventory
    15. quarkus.datasource.inventory.username=username2
    16. quarkus.datasource.inventory.min-size=2
    17. quarkus.datasource.inventory.max-size=12

    Notice there’s an extra bit in the key.The syntax is as follows: .

    Named Datasource Injection

    When using multiple datasources, each DataSource also has the io.quarkus.agroal.DataSource qualifier with the name of the datasource in the property as the value.Using the above properties to configure three different datasources, you can also inject each one as follows:

    If you are using the quarkus-smallrye-health extension, quarkus-agroal will automatically add a readiness health checkto validate the datasource.

    So when you access the /health/ready endpoint of your application you will have information about the datasource validation status.If you have multiple datasources, all datasources will be checked and the status will be DOWN as soon as there is one datasource validation failure.

    This behavior can be disabled via the property quarkus.datasource.health.enabled.

    Narayana Transaction Manager integration

    If the Narayana JTA extension is also available, integration is automatic.

    You can override this by setting the transactions configuration property - see the Configuration Reference below.

    Testing with in-memory databases

    Some databases like H2 and Derby are commonly used in "embedded mode" as a facility to run quick integration tests.

    Our suggestion is to use the real database you intend to use in production; container technologies made this simple enough so you no longer have an excuse. Still, there are sometimesgood reasons to also want the ability to run quick integration tests using the JVM powered databases,so this is possible as well.

    It is important to remember that when configuring H2 (or Derby) to use the embedded engine,this will work as usual in JVM mode but such an application will not compile into a native image, as the Quarkus extensions only cover for making the JDBC client code compatible with the native compilation step: embedding the whole database engine into a native image is currently not implemented.

    If you plan to run such integration tests in the JVM exclusively, it will of course work as usual.

    If you want the ability to run such integration test in both JVM and/or native images, we have some cool helpers for you: just add either @QuarkusTestResource(H2DatabaseTestResource.class) or @QuarkusTestResource(DerbyDatabaseTestResource.class) on any class in your integration tests, this will make sure the testsuite starts (and stops) the embedded database into a separate process as necessary to run your tests.

    These additional helpers are provided by the artifacts having Maven coordinates io.quarkus:quarkus-test-h2:1.0.0.CR1 and io.quarkus:quarkus-test-derby:1.0.0.CR1, respectively for H2 and Derby.

    Follows an example for H2:

    1. package my.app.integrationtests.db;
    3. import io.quarkus.test.common.QuarkusTestResource;
    4. import io.quarkus.test.h2.H2DatabaseTestResource;
    6. @QuarkusTestResource(H2DatabaseTestResource.class)
    7. public class TestResources {
    8. }

    This will allow you to test your application even when it’s compiled into a native image,while the database will run in the JVM as usual.

    1. quarkus.datasource.url=jdbc:h2:tcp://localhost/mem:test
    2. quarkus.datasource.driver=org.h2.Driver

    Configuration property fixed at build time - ️ Configuration property overridable at runtime