Install SQL Server Java Language Extension on Linux

Applies to: SQL Server 2019 (15.x) on Linux and later versions

Learn how to install the Java Language Extension component for SQL Server on Linux. The Java Language Extension is part of SQL Server Language Extensions and an add-on to the Database Engine.

Although you can install the Database Engine and Language Extensions concurrently, it's a best practice to install and configure the SQL Server Database Engine first so that you can resolve any issues before adding more components.

Prerequisites

• Your Linux distribution must be supported by SQL Server. Containers are covered separately in a later bullet. Supported distributions include:

  • Red Hat Enterprise Linux (RHEL)
  • SUSE Linux Enterprise Server (SLES)
  • Ubuntu

• You need a query editor to run Transact-SQL (T-SQL) commands for post-install configuration and validation. We recommend the MSSQL extension for Visual Studio Code. It's a free download that runs on Linux.

• Language Extensions is also supported on Linux containers. Prebuilt containers with Language Extensions aren't available, but you can create one from the SQL Server containers by using an example template available on GitHub.

• Language Extensions and Machine Learning Services are installed by default on SQL Server Big Data Clusters. If you use Big Data Clusters, you don't need to follow the steps in this article.

Package list

On an internet-connected device, you download and install packages independently of the Database Engine by using the package installer for each operating system. The following table describes all available packages.

Install Java language extension

# Install as root or sudo
sudo yum install mssql-server-extensibility-java

# Install as root or sudo
sudo apt-get install mssql-server-extensibility-java

# Install as root or sudo
sudo zypper install mssql-server-extensibility-java

Post-install configuration (required)

1. Grant permissions on Linux

   You don't need to perform this step if you use external libraries. External libraries are the recommended approach. For help with creating an external library from your jar file, see CREATE EXTERNAL LIBRARY.

   If you aren't using external libraries, you need to provide SQL Server with permissions to execute the Java classes in your jar.

   To grant read and execute access to a jar file, run the following chmod command on the jar file. Always put your class files in a jar when you work with SQL Server. For help with creating a jar, see Create a Java .jar file from class files.

   chmod ug+rx <MyJarFile.jar>
   

   You also need to give mssql_satellite permissions to read and execute the jar file.

   chown mssql_satellite:mssql_satellite <MyJarFile.jar>
   

   Additional configuration is primarily through the mssql-conf tool.

2. Add the mssql user account used to run the SQL Server service. This step is required if you haven't run the setup previously.

   sudo /opt/mssql/bin/mssql-conf setup
   

3. Enable outbound network access. Outbound network access is disabled by default. To enable outbound requests, set the outboundnetworkaccess Boolean property with the mssql-conf tool. For more information, see Configure SQL Server on Linux with mssql-conf.

   # Run as SUDO or root
   # Enable outbound requests over the network
   sudo /opt/mssql/bin/mssql-conf set extensibility outboundnetworkaccess 1
   

4. Restart the SQL Server Launchpad service and the Database Engine instance to read the updated values from the INI file. A restart message reminds you whenever you modify an extensibility-related setting.

   systemctl restart mssql-launchpadd
   systemctl restart mssql-server.service
   

5. Enable external script execution. You can connect to an instance of SQL Server using any familiar SQL Server client tool, such as sqlcmd, SQL Server Management Studio (SSMS), or the MSSQL extension for Visual Studio Code.

   EXECUTE sp_configure 'external scripts enabled', 1;
   
   RECONFIGURE WITH OVERRIDE;
   

6. Restart the mssql-launchpadd service again.

7. For each database where you want to use language extensions, register the external language with CREATE EXTERNAL LANGUAGE. See the next section for steps.

Register external language

For each database where you want to use language extensions, register the external language with CREATE EXTERNAL LANGUAGE.

The following example adds an external language called Java to a database on SQL Server on Linux.

CREATE EXTERNAL LANGUAGE Java
FROM (
    CONTENT = N'/opt/mssql-extensibility/lib/java-lang-extension.tar.gz',
    FILE_NAME = 'javaextension.so',
    ENVIRONMENT_VARIABLES = N'{"JRE_HOME":"/opt/mssql/lib/zulu-jre-11"}'
);

For the Java extension, the environment variable JRE_HOME determines the path to find and initialize the JVM.

The CREATE EXTERNAL LANGUAGE DDL provides an ENVIRONMENT_VARIABLES parameter to set environment variables for the process that hosts the extension. Use this parameter to set environment variables that external language extensions require.

For more information, see CREATE EXTERNAL LANGUAGE.

Verify installation

Java feature integration doesn't include libraries, but you can run grep -r JRE_HOME /etc to confirm the JRE_HOME environment variable exists.

To validate installation, run a T-SQL script that executes a system stored procedure invoking Java. You need a query tool for this task. You can connect to an instance of SQL Server using any familiar SQL Server client tool, such as sqlcmd, SQL Server Management Studio (SSMS), or the MSSQL extension for Visual Studio Code.

Limitations

Implied authentication isn't available on Linux. Java code running in the external process can't connect back to the server to access data or other resources.

Resource governance

Linux and Windows have parity for resource governance for external resource pools, but the statistics for sys.dm_resource_governor_external_resource_pools currently have different units on Linux.

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