Pub/Sub ordering guarantees

pperestoronin · 07-13-2022 05:37 AM

I am going to use Pub/Sub platform for rtdn processing. I am a bit confused of some guarantees (if they exist, it will make my tasks much easier) of Pub/Sub platform, so I want to ask:

1. is it possible for message with less publishTime (for eg. publishTime = 12:00, found in request = 12:02) appear later, than one with bigger publishTime (publishTime = 12:01, found in request = 12:01)?

2. [wrong for sure if (1) is possible] are messages ordered by publishTime in https://cloud.google.com/pubsub/docs/reference/rest/v1/projects.subscriptions/pull? Is it guranteed if I'll request 2 batches (with aknowleding of all subs), that for every message1 from first batch and any message2 from second one `message1.publishTime <= message2.publishTime` will be true?

raul_saucedo

You can’t modify the publish time because it's an attribute for a message published. You can get this time only from a message. You can read more information about this attribute.