Which component of the Push Notifications feature stores the messages that are ready to be sent?

Push Notifications in Oracle APEX enable real-time messaging to users’ devices via Progressive Web

App (PWA) capabilities. The component responsible for storing messages is:

A . Queue: The Push Notification Queue (managed internally by APEX and accessible via APIs like

APEX_PWA.PUSH_QUEUE) temporarily holds messages scheduled for delivery. When a notification is

created (e.g., via APEX_PWA.SEND), it’s added to this queue, awaiting processing by the APEX mail

system or an external push service. The queue ensures reliable delivery, even if the user is offline

temporarily, as messages are dispatched once connectivity is restored.

B . Application: The application defines the PWA settings and logic but doesn’t store messages; it’s

the container, not the storage mechanism.

C . Subscription: Represents user device registrations (stored in APEX_APPL_PUSH_SUBSCRIPTIONS),

not the messages themselves. Subscriptions link devices to the app for delivery, not queuing.

Technical Insight: The queue is a database-backed structure, leveraging Oracle’s job scheduling (e.g.,

DBMS_SCHEDULER) to process entries. For example, calling APEX_PWA.SEND(p_message => 'Promo

Alert!') adds an entry to the queue, which is then pushed to subscribed devices.

Use Case: A retail app queues a "Sale starts now!" message for 1,000 users, ensuring orderly delivery

without overwhelming the server.

Pitfall: If the queue isn’t periodically pushed (e.g., via APEX_PWA.PUSH_QUEUE), messages may

delay.

Reference: Oracle APEX 23.2 Documentation - "Managing Push Notifications" under APEX_PWA

Package.