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    <div>
     <h4 class="title">
      <a name="group-replication-changing-group-mode">
      </a>
      20.5.1.2 Changing the Group Mode
     </h4>
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   </div>
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  <a class="indexterm" name="idm46045133575024">
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  <p>
   This section explains how to change the mode which a group is
        running in, either single or multi-primary. The functions used
        to change a group's mode can be run on any member.
  </p>
  <div class="simplesect">
   <div class="titlepage">
    <div>
     <div class="simple">
      <h5 class="title">
       <a name="group-replication-switch-to-single">
       </a>
       Changing to Single-Primary Mode
      </h5>
     </div>
    </div>
   </div>
   <a class="indexterm" name="idm46045133571840">
   </a>
   <a class="indexterm" name="idm46045133570336">
   </a>
   <a class="indexterm" name="idm46045133569216">
   </a>
   <a class="indexterm" name="idm46045133567728">
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   <p>
    Use the
    <a class="link" href="group-replication-functions-for-mode.html#function_group-replication-switch-to-single-primary-mode">
     <code class="literal">
      group_replication_switch_to_single_primary_mode()
     </code>
    </a>
    function to change a group running in multi-primary mode to
          single-primary mode by issuing:
   </p>
   <div class="copytoclipboard-wrapper">
    <pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa37273645"><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-sql"><span class="token keyword">SELECT</span> group_replication_switch_to_single_primary_mode<span class="token punctuation">(</span><span class="token punctuation">)</span></code></pre>
   </div>
   <p>
    When you change to single-primary mode, strict consistency
          checks are also disabled on all group members, as required in
          single-primary mode
          (
    <a class="link" href="group-replication-system-variables.html#sysvar_group_replication_enforce_update_everywhere_checks">
     <code class="literal">
      group_replication_enforce_update_everywhere_checks=OFF
     </code>
    </a>
    ).
   </p>
   <p>
    If no string is passed in, the election of the new primary in
          the resulting single-primary group follows the election
          policies described in
    <a class="xref" href="group-replication-single-primary-mode.html" title="20.1.3.1 Single-Primary Mode">
     Section 20.1.3.1, “Single-Primary Mode”
    </a>
    . To
          override the election process and configure a specific member
          of the multi-primary group as the new primary in the process,
          get the
    <a class="link" href="replication-options.html#sysvar_server_uuid">
     <code class="literal">
      server_uuid
     </code>
    </a>
    of the
          member and pass it to
    <a class="link" href="group-replication-functions-for-mode.html#function_group-replication-switch-to-single-primary-mode">
     <code class="literal">
      group_replication_switch_to_single_primary_mode()
     </code>
    </a>
    .
          For example, issue:
   </p>
   <div class="copytoclipboard-wrapper">
    <pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa1545405"><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-sql"><span class="token keyword">SELECT</span> group_replication_switch_to_single_primary_mode<span class="token punctuation">(</span><em class="replaceable">member_uuid</em><span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
   </div>
  </div>
  <div class="simplesect">
   <div class="titlepage">
    <div>
     <div class="simple">
      <h5 class="title">
       <a name="group-replication-switch-to-multi">
       </a>
       Changing to Multi-Primary Mode
      </h5>
     </div>
    </div>
   </div>
   <a class="indexterm" name="idm46045133553520">
   </a>
   <a class="indexterm" name="idm46045133552016">
   </a>
   <a class="indexterm" name="idm46045133550896">
   </a>
   <a class="indexterm" name="idm46045133549408">
   </a>
   <p>
    Use the
    <a class="link" href="group-replication-functions-for-mode.html#function_group-replication-switch-to-multi-primary-mode">
     <code class="literal">
      group_replication_switch_to_multi_primary_mode()
     </code>
    </a>
    function to change a group running in single-primary mode to
          multi-primary mode by issuing:
   </p>
   <div class="copytoclipboard-wrapper">
    <pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa64055157"><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-sql"><span class="token keyword">SELECT</span> group_replication_switch_to_multi_primary_mode<span class="token punctuation">(</span><span class="token punctuation">)</span></code></pre>
   </div>
   <p>
    After some coordinated group operations to ensure the safety
          and consistency of your data, all members which belong to the
          group become primaries.
   </p>
   <p>
    When you change a group from single-primary mode to
          multi-primary mode, members are automatically placed in
          read-only mode if they are running a later MySQL server
          version than the lowest version present in the group.
   </p>
   <p>
    While the action runs, you can check its progress by issuing
          the following
    <a class="link" href="select.html" title="15.2.13 SELECT Statement">
     <code class="literal">
      SELECT
     </code>
    </a>
    statement:
   </p>
   <div class="copytoclipboard-wrapper">
    <pre class="programlisting language-sql"><div class="docs-select-all right" id="sa10637400"><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-sql"><span class="token keyword">SELECT</span> event_name<span class="token punctuation">,</span> work_completed<span class="token punctuation">,</span> work_estimated <span class="token keyword">FROM</span> performance_schema<span class="token punctuation">.</span>events_stages_current <span class="token keyword">WHERE</span> event_name <span class="token operator">LIKE</span> <span class="token string">"%stage/group_rpl%"</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> event_name                                                           <span class="token punctuation">|</span> work_completed <span class="token punctuation">|</span> work_estimated <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> stage/group_rpl/Multi<span class="token punctuation">-</span>primary Switch: applying buffered transactions <span class="token punctuation">|</span>              0 <span class="token punctuation">|</span>              1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
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