nats: error: could not Acknowledge message: nats: message does not have a reply

[sanyuanya]

nats stream info QTEST
Information for Stream QTEST created 2024-05-12 17:19:26

          Subjects: qtest.*
          Replicas: 1
           Storage: File

Options:

         Retention: WorkQueue
   Acknowledgments: true
    Discard Policy: New
  Duplicate Window: 2m0s
        Direct Get: true
 Allows Msg Delete: true
      Allows Purge: true
    Allows Rollups: true

Limits:

  Maximum Messages: 10

Maximum Per Subject: unlimited
Maximum Bytes: unlimited
Maximum Age: unlimited
Maximum Message Size: unlimited
Maximum Consumers: unlimited

State:

          Messages: 10
             Bytes: 440 B
    First Sequence: 1 @ 2024-05-12 17:20:59 UTC
     Last Sequence: 10 @ 2024-05-12 17:21:40 UTC
  Active Consumers: 1
Number of Subjects: 1

---

nats con info
? Select a Stream QTEST
? Select a Consumer cjCon
Information for Consumer QTEST > cjCon created 2024-05-12T17:20:42+08:00

Configuration:

                Name: cjCon
    Delivery Subject: pull
      Filter Subject: qtest.cj
      Deliver Policy: All
          Ack Policy: Explicit
            Ack Wait: 30.00s
       Replay Policy: Instant
     Max Ack Pending: 1,000
        Flow Control: false

State:

Last Delivered Message: Consumer sequence: 0 Stream sequence: 0
Acknowledgment Floor: Consumer sequence: 0 Stream sequence: 0
Outstanding Acks: 0 out of maximum 1,000
Redelivered Messages: 0
Unprocessed Messages: 10
Active Interest: No interest

---

nats pub qtest.cj --count=9 --sleep 500ms "hello{{Count}}"
17:21:37 Published 6 bytes to "qtest.cj"
17:21:37 Published 6 bytes to "qtest.cj"
17:21:38 Published 6 bytes to "qtest.cj"
17:21:38 Published 6 bytes to "qtest.cj"
17:21:39 Published 6 bytes to "qtest.cj"
17:21:39 Published 6 bytes to "qtest.cj"
17:21:40 Published 6 bytes to "qtest.cj"
17:21:40 Published 6 bytes to "qtest.cj"
17:21:41 Published 6 bytes to "qtest.cj"

---

nats con next QTEST cjCon
--- subject: _INBOX.Y3pwquV4nPWrj0qtpa7p57.xBWD303m

Headers:

Status: 409
Description: Consumer is push based

Data:

nats: error: could not Acknowledge message: nats: message does not have a reply