Packetbeat loss data when monitor mysql

[Romber_Li]

I deployed packbeat on a mysql server to capture mysql traffic, and then send to the kafka,
but I found that, QPS that was sent to kafka was much lower than I saw in monitoring system(I use Percona Monitoring and Management(PMM) to monitor mysql database).
after checking the packbeat log, we found that there are many "unmatched_responses", so here are my questions:

1. what does "unmatched_responses" mean? I did not find explain in document, did I miss something?
2. as you can see the monitor screenshot blow, the QPS of mysql server is about 20000,
   but as the log of packetbeat, it only published approximately 200000 to kafka, this log was printed every 30secons, which means 6666 QPS, which is much smaller than what PMM shows.why is that?
3. even there are huge amount of "unmatched_responses"(approximately 140000), the summary of "published" + "unmatched_responses" is 340000, divided by 30, that is 11333, still much smaller than what PMM shows, so how can I get the same data between PMM and packetbeat?

QPS showed by PMM:

packbeat log:

2020-03-26T16:50:10.995+0800    INFO    [monitoring]    log/log.go:145  Non-zero metrics in the last 30s        {"monitoring": {"metrics": {"beat":{"cpu":{"system":{"ticks":53030,"time":{"ms":6254}},"total":{"ticks":965690,"time":{"ms":140400},"value":965690},"user":{"ticks":912660,"time":{"ms":134146}}},"handles":{"limit":{"hard":4096,"soft":1024},"open":18},"info":{"ephemeral_id":"f65eecf1-0f47-4452-9e38-2f70d532a1a8","uptime":{"ms":210037}},"memstats":{"gc_next":50600592,"memory_alloc":51149800,"memory_total":230887573952,"rss":24576},"runtime":{"goroutines":62}},"libbeat":{"config":{"module":{"running":0}},"output":{"events":{"acked":200704,"active":256,"batches":785,"total":200960}},"outputs":{"kafka":{"bytes_read":1865808,"bytes_write":38026679}},"pipeline":{"clients":1,"events":{"active":306,"failed":5157,"published":200925,"total":206082},"queue":{"acked":200704}}},"mysql":{"unmatched_requests":540,"**unmatched_responses":138995**},"system":{"load":{"1":7.49,"15":7.42,"5":7.1,"norm":{"1":0.156,"15":0.1546,"5":0.1479}}},"tcp":{"dropped_because_of_gaps":17}}}}

packetbeat.yml(I masked the IP address):

path.home: /data/app/packetbeat
max_procs: 6
logging:
  level: info
  to_files: true
  files:
    name: packetbeat.log
    keepfiles: 5
    rotateeverybytes: 20971520
    permissions: 0644
    interval: 168h

packetbeat.ignore_outgoing: true
packetbeat.interfaces.device: any
packetbeat.interfaces.type: af_packet
packetbeat.interfaces.buffer_size_mb: 2048

packetbeat.flows:
  enabled: false

processors:
- add_locale:
    format: offset
- drop_fields:
    fields: ["host", "ecs", "agent"]

# packetbeat.interfaces.bpf_filter: "port 3306 or port 7001 or port 7002"
packetbeat.protocols:
  # mysql
  - type: mysql
    enabled: true
    ports: [3306, 3307, 3308, 3309, 3310]
    send_request: false
    send_response: false
    max_rows: 100
    max_row_length: 10485760
    processors:
    - include_fields:
        fields: ["name", "tags", "client", "server", "type", "method", "event", "query", "mysql"]
    - add_fields:
        target: ''
        fields:
          cluster_name: ${cluster_name_mysql:mysql}
    - drop_fields:
        fields: ["event.dataset", "event.kind", "event.category"]
  # redis
  - type: redis
    enabled: false
    ports: [6379, 7001, 7002]
    send_request: false
    send_response: false
    queue_max_bytes: 1048576
    queue_max_messages: 20000
    processors:
    - include_fields:
        fields: ["name", "tags", "client", "server", "type", "method", "resource", "event", "redis"]
    - add_fields:
        target: ''
        fields:
          cluster_name: ${cluster_name_redis:redis}
    - drop_fields:
        fields: ["event.dataset", "event.kind", "event.category"]

queue.mem:
  events: 10240
  flush.min_events: 256
  flush.timeout: 1s

# output configuration
# file
output:
  file:
    enabled: false
    path: "/data/app/packetbeat/data"
    filename: "packetbeat_file.out"
    number_of_file: 5
    rotate_every_kb: 20480
    #codec.json:
    #  pretty: true
    #codec.format:
    #  string: '%{[@timestamp]} %{[message]}'
# kafka
  kafka:
    enabled: true
    hosts: ["xxx.xxx.xxx.xxx:9092", "xxx.xxx.xxx.xxx:9092", "xxx.xxx.xxx.xxx:9092", "xxx.xxx.xxx.xxx:9092", "xxx.xxx.xxx.xxx:9092"]
    topic: "packetbeat_mysql_01"
    partition.round_robin:
      reachable_only: true
    metadata:
      refresh_frequency: 5m
      full: false
    #codec.json:
    #  pretty: true
    #codec.format:
    #  string: '%{[@timestamp]} %{[message]}'