Hi,
I'm testing Vercel Queues push-mode concurrency in a Production project.
Environment:
- /queue 0.8.0
- queue/v2beta push trigger
- one topic
- one consumer group / route
- Next.js 16
- Fluid compute
- two messages published back-to-back in a single publisher invocation
Publisher result:
- selected: 2
- published: 2
- batchSize: 2
- two distinct Queue message IDs
Our application allows two concurrent workers:
- database maxSlots = 2
- no mutex / semaphore / singleton promise
- no global DB lock
- no capacity retry occurred
- each message was processed on deliveryCount 1
However, the executions were serial.
Message/photo B: processing start: 12:46:48.424 UTC processing complete: 12:46:54.945 UTC
Message/photo A: processing start: 12:47:08.033 UTC processing complete: 12:47:17.385 UTC
The second worker therefore started around 13 seconds after the first worker completed.
The Vercel documentation says:
"In push mode, you can set a maximum concurrency per consumer group."
But the documented queue/v2beta trigger schema does not expose a maxConcurrency option, and /queue does not appear to expose one for push consumers.
Could you please clarify:
-
What is the default maximum concurrency for a queue/v2beta push consumer group?
-
Is maximum push concurrency configurable today?
-
If so, where is it configured:
- vercel.json
- dashboard
- API
- support-side/internal setting?
-
Can you confirm the current maximum concurrency for the consumer group in our project?
-
With concurrency > 1, should two messages sent milliseconds apart normally result in overlapping function invocations?
-
Is a 10-20 second delay before delivering a second message normal push-mode behavior when only a small number of messages are queued?
-
Does per-deployment topic partitioning impose any serialization within one deployment?
-
Is Vqs-Max-Concurrency relevant to queue/v2beta push consumers, or only to explicit ReceiveMessages / poll-mode calls?
We specifically want two processing workers to be allowed to execute concurrently, while our database remains the authoritative ceiling at maxSlots=2.
Thanks.