<div id="docs-body">
 <div class="section">
  <div class="titlepage">
   <div>
    <div>
     <h4 class="title">
      <a name="performance-schema-replication-group-communication-information-table">
      </a>
      29.12.11.10 The replication_group_communication_information Table
     </h4>
    </div>
   </div>
  </div>
  <a class="indexterm" name="idm46045071146480">
  </a>
  <a class="indexterm" name="idm46045071144960">
  </a>
  <p>
   This table shows group configuration options for the whole
          replication group. The table is available only when Group
          Replication is installed.
  </p>
  <p>
   The
   <code class="literal">
    replication_group_communication_information
   </code>
   table has these columns:
  </p>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      <code class="literal">
       WRITE_CONCURRENCY
      </code>
     </p>
     <p>
      The maximum number of consensus instances that the group
              can execute in parallel. The default value is 10. See
      <a class="xref" href="group-replication-group-write-consensus.html" title="20.5.1.3 Using Group Replication Group Write Consensus">
       Section 20.5.1.3, “Using Group Replication Group Write Consensus”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       PROTOCOL_VERSION
      </code>
     </p>
     <p>
      The Group Replication communication protocol version,
              which determines what messaging capabilities are used.
              This is set to accommodate the oldest MySQL Server version
              that you want the group to support. See
      <a class="xref" href="group-replication-communication-protocol.html" title="20.5.1.4 Setting a Group's Communication Protocol Version">
       Section 20.5.1.4, “Setting a Group's Communication Protocol Version”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       WRITE_CONSENSUS_LEADERS_PREFERRED
      </code>
     </p>
     <p>
      The leader or leaders that Group Replication has
              instructed the group communication engine to use to drive
              consensus. For a group in single-primary mode with the
      <a class="link" href="group-replication-system-variables.html#sysvar_group_replication_paxos_single_leader">
       <code class="literal">
        group_replication_paxos_single_leader
       </code>
      </a>
      system variable set to
      <code class="literal">
       ON
      </code>
      and the
              communication protocol version set to 8.0.27 or later, the
              single consensus leader is the group's primary.
              Otherwise, all group members are used as leaders, so they
              are all shown here. See
      <a class="xref" href="group-replication-single-consensus-leader.html" title="20.7.3 Single Consensus Leader">
       Section 20.7.3, “Single Consensus Leader”
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       WRITE_CONSENSUS_LEADERS_ACTUAL
      </code>
     </p>
     <p>
      The actual leader or leader that the group communication
              engine is using to drive consensus. If a single consensus
              leader is in use for the group, and the primary is
              currently unhealthy, the group communication selects an
              alternative consensus leader. In this situation, the group
              member specified here can differ from the preferred group
              member.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       WRITE_CONSENSUS_SINGLE_LEADER_CAPABLE
      </code>
     </p>
     <p>
      Whether the replication group is capable of using a single
              consensus leader. 1 means that the group was started with
              the use of a single leader enabled
              (
      <a class="link" href="group-replication-system-variables.html#sysvar_group_replication_paxos_single_leader">
       <code class="literal">
        group_replication_paxos_single_leader
              = ON
       </code>
      </a>
      ), and this is still shown if the value of
      <a class="link" href="group-replication-system-variables.html#sysvar_group_replication_paxos_single_leader">
       <code class="literal">
        group_replication_paxos_single_leader
       </code>
      </a>
      has since been changed on this group member. 0 means that
              the group was started with single leader mode disabled
              (
      <a class="link" href="group-replication-system-variables.html#sysvar_group_replication_paxos_single_leader">
       <code class="literal">
        group_replication_paxos_single_leader
              = OFF
       </code>
      </a>
      ), or has a Group Replication communication
              protocol version that does not support the use of a single
              consensus leader (prior to 8.0.27). This information is
              only returned for group members in
      <code class="literal">
       ONLINE
      </code>
      or
      <code class="literal">
       RECOVERING
      </code>
      state.
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       MEMBER_FAILURE_SUSPICIONS_COUNT
      </code>
     </p>
     <p>
      The address of each group member paired with the number of
              times this member has been seen as suspect by the local
              node. This information is displayed in JSON format. For a
              group with three members, the value of this column should
              appear similar to what is shown here:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting language-js"><div class="docs-select-all right" id="sa89961252"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-js"><span class="token punctuation">{</span>
  <span class="token string">"d57da302-e404-4395-83b5-ff7cf9b7e055"</span><span class="token punctuation">:</span> <span class="token number">0</span><span class="token punctuation">,</span>
  <span class="token string">"6ace9d39-a093-4fe0-b24d-bacbaa34c339"</span><span class="token punctuation">:</span> <span class="token number">10</span><span class="token punctuation">,</span>
  <span class="token string">"9689c7c5-c71c-402a-a3a1-2f57bfc2ca62"</span><span class="token punctuation">:</span> <span class="token number">0</span>
<span class="token punctuation">}</span></code></pre>
     </div>
    </li>
   </ul>
  </div>
  <p>
   The
   <code class="literal">
    replication_group_communication_information
   </code>
   table has no indexes.
  </p>
  <p>
   <a class="link" href="truncate-table.html" title="15.1.37 TRUNCATE TABLE Statement">
    <code class="literal">
     TRUNCATE TABLE
    </code>
   </a>
   is not permitted
          for the
   <code class="literal">
    replication_group_communication_information
   </code>
   table.
  </p>
 </div>
 <br/>
</div>
