How to Build Real-Time Alerts from Database Changes

Trigger real-time alerts when your database changes: new high-value orders, inventory dropping below threshold, or customer churn signals. CDC captures database changes; streaming SQL evaluates alert conditions; notifications fire immediately.

Alert Pipeline

PostgreSQL → CDC → RisingWave → Alert Views → Notification Service

Implementation

-- CDC from production database
CREATE TABLE orders (...) FROM pg_source TABLE 'public.orders';
CREATE TABLE inventory (...) FROM pg_source TABLE 'public.inventory';

-- High-value order alert
CREATE MATERIALIZED VIEW high_value_alerts AS
SELECT order_id, customer_id, amount, created_at
FROM orders WHERE amount > 10000 AND created_at > NOW() - INTERVAL '5 minutes';

-- Low inventory alert
CREATE MATERIALIZED VIEW inventory_alerts AS
SELECT sku, product_name, quantity
FROM inventory WHERE quantity < reorder_point AND quantity > 0;

-- Stockout alert
CREATE MATERIALIZED VIEW stockout_alerts AS
SELECT sku, product_name FROM inventory WHERE quantity <= 0;

Notification Delivery

# Poll alert views and send notifications
cursor.execute('SELECT * FROM high_value_alerts')
for alert in cursor.fetchall():
    send_slack_notification(f'High-value order: ${alert[2]} from customer {alert[1]}')

Or use RisingWave's webhook sink for push-based delivery.

Frequently Asked Questions

How fast are alerts from database changes?

With RisingWave's native CDC and 1-second checkpoints, alerts fire within 1-2 seconds of the database change. Compare to batch alerting which checks every few minutes or hours.

Can I alert on complex conditions (joins across tables)?

Yes. Streaming SQL supports full JOIN capabilities. Alert on conditions like 'customer with >3 open tickets AND subscription expiring in <7 days' by joining customer, ticket, and subscription tables via CDC.