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    <div>
     <h2 class="title">
      <a name="group-replication-monitoring">
      </a>
      20.4 Monitoring Group Replication
     </h2>
    </div>
   </div>
  </div>
  <div class="toc">
   <dl class="toc">
    <dt>
     <span class="section">
      <a href="group-replication-gtids.html">
       20.4.1 GTIDs and Group Replication
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="group-replication-server-states.html">
       20.4.2 Group Replication Server States
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="group-replication-replication-group-members.html">
       20.4.3 The replication_group_members Table
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="group-replication-replication-group-member-stats.html">
       20.4.4 The replication_group_member_stats Table
      </a>
     </span>
    </dt>
   </dl>
  </div>
  <a class="indexterm" name="idm46045133752064">
  </a>
  <p>
   You can use the MySQL
   <a class="link" href="performance-schema.html" title="Chapter 29 MySQL Performance Schema">
    Performance
    Schema
   </a>
   to monitor Group Replication. These Performance Schema
    tables display information specific to Group Replication:
  </p>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      <a class="link" href="performance-schema-replication-group-member-stats-table.html" title="29.12.11.15 The replication_group_member_stats Table">
       <code class="literal">
        replication_group_member_stats
       </code>
      </a>
      : See
      <a class="xref" href="group-replication-replication-group-member-stats.html" title="20.4.4 The replication_group_member_stats Table">
       Section 20.4.4, “The replication_group_member_stats Table”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a class="link" href="performance-schema-replication-group-members-table.html" title="29.12.11.16 The replication_group_members Table">
       <code class="literal">
        replication_group_members
       </code>
      </a>
      : See
      <a class="xref" href="group-replication-replication-group-members.html" title="20.4.3 The replication_group_members Table">
       Section 20.4.3, “The replication_group_members Table”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a class="link" href="performance-schema-replication-group-communication-information-table.html" title="29.12.11.10 The replication_group_communication_information Table">
       <code class="literal">
        replication_group_communication_information
       </code>
      </a>
      :
        See
      <a class="xref" href="performance-schema-replication-group-communication-information-table.html" title="29.12.11.10 The replication_group_communication_information Table">
       Section 29.12.11.10, “The replication_group_communication_information Table”
      </a>
      .
     </p>
    </li>
   </ul>
  </div>
  <p>
   These Performance Schema replication tables also show information
    relating to Group Replication:
  </p>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      <a class="link" href="performance-schema-replication-connection-status-table.html" title="29.12.11.13 The replication_connection_status Table">
       <code class="literal">
        replication_connection_status
       </code>
      </a>
      shows
        information regarding Group Replication, such as transactions
        received from the group and queued in the applier queue (relay
        log).
     </p>
    </li>
    <li class="listitem">
     <p>
      <a class="link" href="performance-schema-replication-applier-status-table.html" title="29.12.11.5 The replication_applier_status Table">
       <code class="literal">
        replication_applier_status
       </code>
      </a>
      shows
        the states of channels and threads relating to Group
        Replication. These can also be used to monitor what individual
        worker threads are doing.
     </p>
    </li>
   </ul>
  </div>
  <p>
   Replication channels created by the Group Replication plugin are
    listed here:
  </p>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      <code class="literal">
       group_replication_recovery
      </code>
      : Used for
        replication changes related to distributed recovery.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       group_replication_applier
      </code>
      : Used for the
        incoming changes from the group, to apply transactions coming
        directly from the group.
     </p>
    </li>
   </ul>
  </div>
  <p>
   For information about system variables affecting Group Replication,
    see
   <a class="xref" href="group-replication-system-variables.html" title="20.9.1 Group Replication System Variables">
    Section 20.9.1, “Group Replication System Variables”
   </a>
   . See
   <a class="xref" href="group-replication-status-variables.html" title="20.9.2 Group Replication Status Variables">
    Section 20.9.2, “Group Replication Status Variables”
   </a>
   , for status
    variables providing information about Group Replication.
  </p>
  <p>
   Messages relating to Group Replication lifecycle events other than
    errors are classified as system messages; these are always written
    to the replication group member' error log. You can use this
    information to review the history of a given server's
    membership in a replication group.
  </p>
  <p>
   Some lifecycle events that affect the whole group are logged on
    every group member, such as a new member entering
   <code class="literal">
    ONLINE
   </code>
   status in the group or a primary election.
    Other events are logged only on the member where they take place,
    such as super read only mode being enabled or disabled on the
    member, or the member leaving the group. A number of lifecycle
    events that can indicate an issue if they occur frequently are
    logged as warning messages, including a member becoming unreachable
    and then reachable again, and a member starting distributed recovery
    by state transfer from the binary log or by a remote cloning
    operation.
  </p>
  <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
   <div class="admon-title">
    Note
   </div>
   <p>
    If you are monitoring one or more secondary instances using
    <a class="link" href="mysqladmin.html" title="6.5.2 mysqladmin — A MySQL Server Administration Program">
     <span class="command">
      <strong>
       mysqladmin
      </strong>
     </span>
    </a>
    , you should be aware that a
    <a class="link" href="flush.html#flush-status">
     <code class="literal">
      FLUSH STATUS
     </code>
    </a>
    statement executed by
      this utility creates a GTID event on the local instance which may
      impact future group operations.
   </p>
  </div>
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