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     <h4 class="title">
      <a name="clone-plugin-concurrent-ddl">
      </a>
      7.6.7.4 Cloning and Concurrent DDL
     </h4>
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  </div>
  <p>
   In MySQL 8.4, concurrent DDL is permitted on the
        donor by default. Concurrent DDL support on the donor is
        controlled by the
   <a class="link" href="clone-plugin-options-variables.html#sysvar_clone_block_ddl">
    <code class="literal">
     clone_block_ddl
    </code>
   </a>
   variable.
        Concurrent DDL support can be enabled and disabled dynamically
        using a
   <a class="link" href="set.html" title="13.3.6 The SET Type">
    <code class="literal">
     SET
    </code>
   </a>
   statement like this
        one:
  </p>
  <div class="copytoclipboard-wrapper">
   <pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa31414012"><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">SET</span> <span class="token keyword">GLOBAL</span> clone_block_ddl<span class="token operator">=</span>{<span class="token keyword">OFF</span><span class="token operator">|</span><span class="token keyword">ON</span>}</code></pre>
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  <p>
   The default setting is
   <a class="link" href="clone-plugin-options-variables.html#sysvar_clone_block_ddl">
    <code class="literal">
     clone_block_ddl=OFF
    </code>
   </a>
   , which
        permits concurrent DDL on the donor.
  </p>
  <p>
   Whether the effect of a concurrent DDL operation is cloned or
        not depends on whether the DDL operation finishes before the
        dynamic snapshot is taken by the cloning operation.
  </p>
  <p>
   DDL operations that are not permitted during a cloning operation
        regardless of the
   <a class="link" href="clone-plugin-options-variables.html#sysvar_clone_block_ddl">
    <code class="literal">
     clone_block_ddl
    </code>
   </a>
   setting
        include:
  </p>
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    <li class="listitem">
     <p>
      <code class="literal">
       ALTER TABLE
       <em class="replaceable">
        <code>
         tbl_name
        </code>
       </em>
       DISCARD TABLESPACE;
      </code>
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       ALTER TABLE
       <em class="replaceable">
        <code>
         tbl_name
        </code>
       </em>
       IMPORT TABLESPACE;
      </code>
     </p>
    </li>
    <li class="listitem">
     <p>
      <code class="literal">
       ALTER INSTANCE DISABLE INNODB REDO_LOG;
      </code>
     </p>
    </li>
   </ul>
  </div>
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