Using Liquibase with Amazon Redshift

Amazon Redshift is a fully managed, petabyte-scale data warehouse service in the cloud. An Amazon Redshift data warehouse is a collection of computing resources called nodes. The nodes are organized into a group called a cluster. Each cluster runs an Amazon Redshift engine and contains one or more databases. For more information, see the Amazon Redshift documentation page.

Verified database versions

• Cloud

Prerequisites

1. Download and Install Liquibase on your machine.
2. Ensure Java is installed: Liquibase requires Java to run. If you used the Liquibase Installer, Java is included automatically. Otherwise, you must install Java manually.
3. If you use Liquibase Pro, or a Liquibase Pro extension, confirm that you have a valid license key. For more information, see How to Apply Your Liquibase Pro License Key

Install drivers

CLI users

To use Liquibase and Amazon Redshift, you need two JAR files: JDBC and the Liquibase Redshift extension:

1. Download the Amazon Redshift JDBC 4.2–compatible driver that includes AWS SDK driver-dependent libraries from Amazon, and extract the contents of the ZIP file into the Liquibase /lib folder.
2. Go to the liquibase-redshift repository and download the latest released Liquibase extension liquibase-redshift-<version>.jar file. The latest JAR is in the "Assets" section of the latest release. Alternatively, download it from Maven Central.

To use the Liquibase CLI, place your JAR file(s) in the $LIQUIBASE_HOME/lib directory.

Tip: $LIQUIBASE_HOME is an environment variable that points to the location of the directory where Liquibase is installed on your machine. You can set environment variables using your operating system's shell. The location of $LIQUIBASE_HOME will depend on where Liquibase was installed on your machine.

Maven users

To use Liquibase with Maven, include the driver JAR(s) as a dependency in your pom.xml file. Using this information, Maven automatically downloads the driver JAR from Maven Central when you build your project.

<dependency>
    <groupId>com.amazon.redshift</groupId>
    <artifactId>redshift-jdbc42</artifactId>
    <version>2.1.0.12</version>
</dependency>
<dependency>
    <groupId>org.liquibase.ext</groupId>
    <artifactId>liquibase-redshift</artifactId>
    <version>4.33.0</version>
</dependency>

Make sure that the Liquibase plugin and the database extension have the same version in your POM.

Configure connection

1. Ensure your Amazon Redshift database is configured. You can check the connection to an Amazon Redshift cluster.
2. Specify the database URL in the liquibase.properties file (defaults file), along with other properties you want to set a default value for. Liquibase does not parse the URL. You can either specify the full database connection string or specify the URL using your database's standard connection format:

url: jdbc:redshift://endpoint:port/database

Example: url: jdbc:redshift://<cluster-identifier>.us-east-1.redshift.amazonaws.com:5439/databasename

Note: To get your JDBC connection, see Finding your cluster connection string.

Tip: To apply a Liquibase Pro key to your project, add the following property to the Liquibase properties file: licenseKey: <paste code here>

Test connection

1. Create a text file called changelog (.sql, .yaml, .json, or .xml) in your project directory and add a changeset.

   If you already created a changelog using the init project command, you can use that instead of creating a new file. When adding onto an existing changelog, be sure to only add the changeset and to not duplicate the changelog header.

• SQL example
• YAML example
• JSON example
• XML example

--liquibase formatted sql

--changeset your.name:1
CREATE TABLE test_table (test_id INT NOT NULL, test_column INT, PRIMARY KEY (test_id) NOT ENFORCED)

Tip: Formatted SQL changelogs generated from Liquibase versions before 4.2.0 might cause issues because of the lack of space after a double dash ( -- ). To fix this, add a space after the double dash. For example: -- liquibase formatted sql instead of --liquibase formatted sql and -- changeset myname:create-table instead of --changeset myname:create-table.

databaseChangeLog:
   - changeSet:
       id: 1
       author: your.name
       changes:
       - createTable:
           tableName: test_table
           columns:
           - column:
               name: test_id
               type: INT
               constraints:
                   primaryKey:  true
                   nullable:  false
           - column:
               name: test_column
               type: INT

{
  "databaseChangeLog": [
    {
      "changeSet": {
        "id": "1",
        "author": "your.name",
        "changes": [
          {
            "createTable": {
              "tableName": "test_table",
              "columns": [
                {
                  "column": {
                    "name": "test_id",
                    "type": "INT",
                    "constraints": {
                      "primaryKey": true,
                      "nullable": false
                    }
                  }
                },
                {
                  "column": {
                    "name": "test_column",
                    "type": "INT"
                  }
                }
              ]
            }
          }
        ]
      }
    }
  ]
}

<?xml version="1.0" encoding="UTF-8"?>
<databaseChangeLog
    xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:ext="http://www.liquibase.org/xml/ns/dbchangelog-ext"
    xmlns:pro="http://www.liquibase.org/xml/ns/pro"
    xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
        http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd
        http://www.liquibase.org/xml/ns/dbchangelog-ext
        http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-ext.xsd
        http://www.liquibase.org/xml/ns/pro
        http://www.liquibase.org/xml/ns/pro/liquibase-pro-latest.xsd">

    <changeSet id="1" author="your.name">
        <createTable tableName="test_table">
            <column name="test_id" type="int">
                <constraints primaryKey="true" nullable="false" />
            </column>
            <column name="test_column" type="int"/>
        </createTable>
    </changeSet>

</databaseChangeLog>

2. Navigate to your project folder in the CLI and run the Liquibase status command to see whether the connection is successful:

liquibase status --username=test --password=test --changelog-file=<changelog.xml>

Note: You can specify arguments in the CLI or keep them in the Liquibase properties file.

If your connection is successful, you'll see a message like this:

4 changesets have not been applied to <your_connection_url>
Liquibase command 'status' was executed successfully. 

3. Inspect the deployment SQL with the update-sql command:

liquibase update-sql --changelog-file=<changelog.xml>

If the SQL that Liquibase generates isn't what you expect, you should review your changelog file and make any necessary adjustments.

4. Then execute these changes to your database with the update command:

liquibase update --changelog-file=<changelog.xml>

If your update is successful, Liquibase runs each changeset and displays a summary message ending with:

Liquibase: Update has been successful.
Liquibase command 'update' was executed successfully.

5. From a database UI tool, ensure that your database contains the test_table object you added along with the DATABASECHANGELOG table and DATABASECHANGELOGLOCK table.

Now you're ready to start deploying database changes with Liquibase!

Related links

• Getting started with Amazon Redshift
• Change Types
• Liquibase Commands
• Workflows