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     <h4 class="title">
      <a name="nontransactional-tables">
      </a>
      B.3.4.5 Rollback Failure for Nontransactional Tables
     </h4>
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  <a class="indexterm" name="idm46045053507504">
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  <p>
   If you receive the following message when trying to perform a
   <a class="link" href="commit.html" title="15.3.1 START TRANSACTION, COMMIT, and ROLLBACK Statements">
    <code class="literal">
     ROLLBACK
    </code>
   </a>
   , it
          means that one or more of the tables you used in the
          transaction do not support transactions:
  </p>
  <div class="copytoclipboard-wrapper">
   <pre class="programlisting one-line language-none"><div class="docs-select-all right" id="sa89662393"><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-none">Warning: Some non-transactional changed tables couldn't be rolled back</code></pre>
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  <p>
   These nontransactional tables are not affected by the
   <a class="link" href="commit.html" title="15.3.1 START TRANSACTION, COMMIT, and ROLLBACK Statements">
    <code class="literal">
     ROLLBACK
    </code>
   </a>
   statement.
  </p>
  <p>
   If you were not deliberately mixing transactional and
          nontransactional tables within the transaction, the most
          likely cause for this message is that a table you thought was
          transactional actually is not. This can happen if you try to
          create a table using a transactional storage engine that is
          not supported by your
   <a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
    <span class="command">
     <strong>
      mysqld
     </strong>
    </span>
   </a>
   server (or
          that was disabled with a startup option). If
   <a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
    <span class="command">
     <strong>
      mysqld
     </strong>
    </span>
   </a>
   does not support a storage engine,
          it instead creates the table as a
   <code class="literal">
    MyISAM
   </code>
   table, which is nontransactional.
  </p>
  <p>
   You can check the storage engine for a table by using either
          of these statements:
  </p>
  <div class="copytoclipboard-wrapper">
   <pre class="programlisting language-sql"><div class="docs-select-all right" id="sa33129858"><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">SHOW</span> <span class="token keyword">TABLE</span> <span class="token keyword">STATUS</span> <span class="token operator">LIKE</span> <span class="token string">'<em class="replaceable">tbl_name</em>'</span><span class="token punctuation">;</span>
<span class="token keyword">SHOW</span> <span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> <em class="replaceable">tbl_name</em><span class="token punctuation">;</span></code></pre>
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  <p>
   See
   <a class="xref" href="show-table-status.html" title="15.7.7.38 SHOW TABLE STATUS Statement">
    Section 15.7.7.38, “SHOW TABLE STATUS Statement”
   </a>
   , and
   <a class="xref" href="show-create-table.html" title="15.7.7.11 SHOW CREATE TABLE Statement">
    Section 15.7.7.11, “SHOW CREATE TABLE Statement”
   </a>
   .
  </p>
  <p>
   To check which storage engines your
   <a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
    <span class="command">
     <strong>
      mysqld
     </strong>
    </span>
   </a>
   server supports, use this statement:
  </p>
  <div class="copytoclipboard-wrapper">
   <pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa10454031"><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">SHOW</span> <span class="token keyword">ENGINES</span><span class="token punctuation">;</span></code></pre>
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  <p>
   See
   <a class="xref" href="show-engines.html" title="15.7.7.17 SHOW ENGINES Statement">
    Section 15.7.7.17, “SHOW ENGINES Statement”
   </a>
   for full details.
  </p>
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