Shovel issue were memory accumulates in connection writer and binaries.

shovel_overload

# 1. On serverA Create a queue with 1M messages

bin/runjava com.rabbitmq.perf.PerfTest -y0 -p -u "q1" \
  -s 1000 --id "q1" -ad false -f persistent \
 -h $serverA  \
 -pmessages 1000000


# 2. On server B trigger the memory alarm.
sudo rabbitmqctl set_vm_memory_high_watermark 0


# 3. Shovel messages between Server A and B

curl -v -XPUT https://username:passwd@$serverA/api/parameters/shovel/czasrvyx/my-shovel \
                       -H "content-type: application/json" \
                       -d @- <<EOF
{
  "value": {
    "src-protocol": "amqp091",
    "src-uri": "amqp:///czasrvyx",
    "src-queue": "q1",
    "dest-protocol": "amqp091",
    "dest-uri": "amqps://username:passwd@server-2.rmq2.cloudamqp.com/zwgtwixg",
    "dest-queue": "q2",
    "ack-mode": "on-publish",
    "src-prefetch-count": 1
  }
}
EOF