- name: pool
  type: group
  description: >
    `pool` contains the metrics that were obtained from the PHP-FPM process
    pool.
  release: beta
  fields:
    - name: process_manager
      type: keyword
      description: >
        Static, dynamic or ondemand.
    - name: connections
      type: group
      description: >
        Connection state specific statistics.
      fields:
      - name: accepted
        type: long
        description: >
          The number of incoming requests that the PHP-FPM server has accepted;
          when a connection is accepted it is removed from the listen queue.
      - name: queued
        type: long
        description: >
          The current number of connections that have been initiated, but not
          yet accepted. If this value is non-zero it typically means that all
          the available server processes are currently busy, and there are no
          processes available to serve the next request. Raising
          `pm.max_children` (provided the server can handle it) should help
          keep this number low. This property follows from the fact that
          PHP-FPM listens via a socket (TCP or file based), and thus inherits
          some of the characteristics of sockets.
      - name: max_listen_queue
        type: long
        description: >
          The maximum number of requests in the queue of pending
          connections since FPM has started.
      - name: listen_queue_len
        type: long
        description: >
          The size of the socket queue of pending connections.
    - name: processes
      type: group
      description: >
        Process state specific statistics.
      fields:
      - name: idle
        type: long
        description: >
          The number of servers in the `waiting to process` state (i.e. not
          currently serving a page). This value should fall between the
          `pm.min_spare_servers` and `pm.max_spare_servers` values when the
          process manager is `dynamic`.
      - name: active
        type: long
        description: >
          The number of servers current processing a page - the minimum is `1`
          (so even on a fully idle server, the result will be not read `0`).
      - name: total
        type: long
        description: >
          The number of idle + active processes.
      - name: max_active
        type: long
        description: >
          The maximum number of active processes since FPM has started.
      - name: max_children_reached
        type: long
        description: >
          Number of times, the process limit has been reached,
          when pm tries to start more children (works only for
          pm 'dynamic' and 'ondemand').
    - name: slow_requests
      type: long
      description: >
        The number of times a request execution time has exceeded
        `request_slowlog_timeout`.
    - name: start_since
      type: long
      description: >
        Number of seconds since FPM has started.
    - name: start_time
      type: date
      format: epoch_second
      description: >
        The date and time FPM has started.