KafkaIQ

10.7.4 – Materialized Views

Module: Section 10 – Kafka Ecosystem & Tools
Section: 10.7 – Joins & Enrichment with ksqlDB
Goal: Create queryable materialized views with pull queries

Creating Materialized Views

CREATE TABLE user_stats AS
SELECT
  user_id,
  COUNT(*) AS order_count,
  SUM(amount) AS total_spent,
  AVG(amount) AS avg_order_value
FROM orders
GROUP BY user_id
EMIT CHANGES;

Result: Table with running statistics per user

Pull Queries

Point-in-time lookups:

-- Get specific user stats
SELECT * FROM user_stats WHERE user_id = 123;

-- Get top spenders
SELECT * FROM user_stats 
ORDER BY total_spent DESC 
LIMIT 10;

REST API Integration

curl -X POST http://localhost:8088/query \
  -d '{
    "ksql": "SELECT * FROM user_stats WHERE user_id = 123;"
  }'

Use Case: Serve real-time data to APIs/dashboards

Key Takeaways

  1. Materialized Views: CREATE TABLE AS SELECT
  2. Pull Queries: Point-in-time state lookup
  3. REST API: Serve data to applications

What's Next?

Next Module: 10.8 – ksqlDB in Production