Fix GCP Pub/Sub Subscription Errors

When working with GCP Pub/Sub, you may encounter a configuration error that prevents your data pipeline or messaging system from working. This guide explains the most common mistake with subscription and shows the exact fix.

A Common Mistake

Creating a Pub/Sub subscription without specifying message ordering or exactly-once delivery, allowing duplicate messages and out-of-order delivery.

The incorrect command:

gcloud pubsub subscriptions create my-sub --topic=my-topic

Error output:

Created subscription [my-sub].
Default: message ordering disabled, exactly-once delivery disabled. If the publisher sends messages with ordering keys, they may be delivered out of order. Network issues cause publishers to retry, creating duplicate messages.

The Correct Approach

The right way to configure subscription in GCP Pub/Sub:

gcloud pubsub subscriptions create my-sub --topic=my-topic --enable-message-ordering --enable-exactly-once-delivery --ack-deadline=60

Successful result:

Created subscription [my-sub].
Message ordering: enabled (messages with same ordering key are delivered in order).
Exactly-once delivery: enabled (no duplicates).
Ack deadline: 60 seconds.

How to Prevent This

Enable message ordering for events that must be processed in sequence. Exactly-once delivery eliminates duplicates (higher latency). Choose ack deadline based on processing time (10-600s). Subscription type (pull vs push) depends on consumer architecture.

FAQ

Built by the developers of Doda Browser, DodaZIP, and Durga Antivirus Pro. Secure your cloud with DodaTech.