Prerequisites

• Docker running via Docker Desktop or Docker Engine
• Docker Compose. Ensure that the command docker compose version succeeds.

Run the commands

Clone the confluentinc/tutorials GitHub repository (if you haven't already) and navigate to the tutorials directory:

git clone git@github.com:confluentinc/tutorials.git
cd tutorials

Start ksqlDB and Kafka:

docker compose -f ./docker/docker-compose-ksqldb.yml up -d

Next, open the ksqlDB CLI:

docker exec -it ksqldb-cli ksql http://ksqldb-server:8088

Run the following SQL statements to create the movies stream backed by Kafka running in Docker and populate it with test data.

CREATE STREAM movies (id INT, title VARCHAR, genre VARCHAR)
    WITH (KAFKA_TOPIC='movies',
          PARTITIONS=1,
          VALUE_FORMAT='AVRO');

INSERT INTO movies (id, title, genre) VALUES (1, 'Twisters::2024', 'drama');
INSERT INTO movies (id, title, genre) VALUES (2, 'Unfrosted::2024', 'comedy');
INSERT INTO movies (id, title, genre) VALUES (3, 'Family Switch::2023', 'comedy');

Next, run the following CREATE STREAM AS SELECT statements to create new rekeyed streams. The first rekeys by a value (the id field), and the second rekeys by the result of the SPLIT scalar function. Note that we first tell ksqlDB to consume from the beginning of the stream.

SET 'auto.offset.reset'='earliest';

CREATE STREAM movies_by_id
    WITH (KAFKA_TOPIC='movies_by_id') AS
SELECT *
FROM movies
PARTITION BY id;

CREATE STREAM movies_by_title
    WITH (KAFKA_TOPIC='movies_by_title') AS
        SELECT *
        FROM movies
        PARTITION BY SPLIT(title, '::')[1];

If you run the following PRINT query, you can see that the key of the movies_by_title stream is the expected title:

PRINT movies_by_title;

The result will include the expected title keys:

key: Twisters
key: Unfrosted
key: Family Switch

When you are finished, exit the ksqlDB CLI by entering CTRL-D and clean up the containers used for this tutorial by running:

docker compose -f ./docker/docker-compose-ksqldb.yml down

Prerequisites

• A Confluent Cloud account
• The Confluent CLI installed on your machine

Create Confluent Cloud resources

Login to your Confluent Cloud account:

confluent login --prompt --save

Install a CLI plugin that will streamline the creation of resources in Confluent Cloud:

confluent plugin install confluent-cloud_kickstart

Run the following command to create a Confluent Cloud environment and Kafka cluster. This will create resources in AWS region us-west-2 by default, but you may override these choices by passing the --cloud argument with a value of aws, gcp, or azure, and the --region argument that is one of the cloud provider's supported regions, which you can list by running confluent kafka region list --cloud <CLOUD PROVIDER>

confluent cloud-kickstart --name ksqldb-tutorial \
  --environment-name ksqldb-tutorial \
  --output-format stdout

Now, create a ksqlDB cluster by first getting your user ID of the form u-123456 when you run this command:

confluent iam user list

And then create a ksqlDB cluster called ksqldb-tutorial with access linked to your user account:

confluent ksql cluster create ksqldb-tutorial \
  --credential-identity <USER ID>

Run the commands

Login to the Confluent Cloud Console. Select Environments in the lefthand navigation, and then click the ksqldb-tutorial environment tile. Click the ksqldb-tutorial Kafka cluster tile, and then select ksqlDB in the lefthand navigation.

The cluster may take a few minutes to be provisioned. Once its status is Up, click the cluster name and scroll down to the editor.

In the query properties section at the bottom, change the value for auto.offset.reset to Earliest so that ksqlDB will consume from the beginning of the stream we create.

Enter the following statements in the editor and click Run query. This creates the movies stream and populates it with test data.

CREATE STREAM movies (id INT, title VARCHAR, genre VARCHAR)
    WITH (KAFKA_TOPIC='movies',
          PARTITIONS=1,
          VALUE_FORMAT='AVRO');

INSERT INTO movies (id, title, genre) VALUES (1, 'Twisters::2024', 'drama');
INSERT INTO movies (id, title, genre) VALUES (2, 'Unfrosted::2024', 'comedy');
INSERT INTO movies (id, title, genre) VALUES (3, 'Family Switch::2023', 'comedy');

Next, create new rekeyed streams. The first is rekeyed by a value (the id field), and the second rekeys by the result of the SPLIT scalar function. Paste these queries in the editor and click Run query.

CREATE STREAM movies_by_id
    WITH (KAFKA_TOPIC='movies_by_id') AS
SELECT *
FROM movies
PARTITION BY id;

CREATE STREAM movies_by_title
    WITH (KAFKA_TOPIC='movies_by_title') AS
        SELECT *
        FROM movies
        PARTITION BY SPLIT(title, '::')[1];

If you run the following DESCRIBE query, you can see that the key of the movies_by_title stream is the expected title:

DESCRIBE movies_by_title;

Clean up

When you are finished, delete the ksqldb-tutorial environment by first getting the environment ID of the form env-123456 corresponding to it:

confluent environment list

Delete the environment, including all resources created for this tutorial:

confluent environment delete <ENVIRONMENT ID>