<div id="docs-body">
 <div class="chapter">
  <div class="titlepage">
   <div>
    <div>
     <h1 class="title">
      <a name="storage-engines">
      </a>
      Chapter 18 Alternative Storage Engines
     </h1>
    </div>
   </div>
  </div>
  <div class="toc">
   <p>
    <b>
     Table of Contents
    </b>
   </p>
   <dl class="toc">
    <dt>
     <span class="section">
      <a href="storage-engine-setting.html">
       18.1 Setting the Storage Engine
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="myisam-storage-engine.html">
       18.2 The MyISAM Storage Engine
      </a>
     </span>
    </dt>
    <dd>
     <dl>
      <dt>
       <span class="section">
        <a href="myisam-start.html">
         18.2.1 MyISAM Startup Options
        </a>
       </span>
      </dt>
      <dt>
       <span class="section">
        <a href="key-space.html">
         18.2.2 Space Needed for Keys
        </a>
       </span>
      </dt>
      <dt>
       <span class="section">
        <a href="myisam-table-formats.html">
         18.2.3 MyISAM Table Storage Formats
        </a>
       </span>
      </dt>
      <dt>
       <span class="section">
        <a href="myisam-table-problems.html">
         18.2.4 MyISAM Table Problems
        </a>
       </span>
      </dt>
     </dl>
    </dd>
    <dt>
     <span class="section">
      <a href="memory-storage-engine.html">
       18.3 The MEMORY Storage Engine
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="csv-storage-engine.html">
       18.4 The CSV Storage Engine
      </a>
     </span>
    </dt>
    <dd>
     <dl>
      <dt>
       <span class="section">
        <a href="se-csv-repair.html">
         18.4.1 Repairing and Checking CSV Tables
        </a>
       </span>
      </dt>
      <dt>
       <span class="section">
        <a href="se-csv-limitations.html">
         18.4.2 CSV Limitations
        </a>
       </span>
      </dt>
     </dl>
    </dd>
    <dt>
     <span class="section">
      <a href="archive-storage-engine.html">
       18.5 The ARCHIVE Storage Engine
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="blackhole-storage-engine.html">
       18.6 The BLACKHOLE Storage Engine
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="merge-storage-engine.html">
       18.7 The MERGE Storage Engine
      </a>
     </span>
    </dt>
    <dd>
     <dl>
      <dt>
       <span class="section">
        <a href="merge-table-advantages.html">
         18.7.1 MERGE Table Advantages and Disadvantages
        </a>
       </span>
      </dt>
      <dt>
       <span class="section">
        <a href="merge-table-problems.html">
         18.7.2 MERGE Table Problems
        </a>
       </span>
      </dt>
     </dl>
    </dd>
    <dt>
     <span class="section">
      <a href="federated-storage-engine.html">
       18.8 The FEDERATED Storage Engine
      </a>
     </span>
    </dt>
    <dd>
     <dl>
      <dt>
       <span class="section">
        <a href="federated-description.html">
         18.8.1 FEDERATED Storage Engine Overview
        </a>
       </span>
      </dt>
      <dt>
       <span class="section">
        <a href="federated-create.html">
         18.8.2 How to Create FEDERATED Tables
        </a>
       </span>
      </dt>
      <dt>
       <span class="section">
        <a href="federated-usagenotes.html">
         18.8.3 FEDERATED Storage Engine Notes and Tips
        </a>
       </span>
      </dt>
      <dt>
       <span class="section">
        <a href="federated-storage-engine-resources.html">
         18.8.4 FEDERATED Storage Engine Resources
        </a>
       </span>
      </dt>
     </dl>
    </dd>
    <dt>
     <span class="section">
      <a href="example-storage-engine.html">
       18.9 The EXAMPLE Storage Engine
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="storage-engines-other.html">
       18.10 Other Storage Engines
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="pluggable-storage-overview.html">
       18.11 Overview of MySQL Storage Engine Architecture
      </a>
     </span>
    </dt>
    <dd>
     <dl>
      <dt>
       <span class="section">
        <a href="pluggable-storage.html">
         18.11.1 Pluggable Storage Engine Architecture
        </a>
       </span>
      </dt>
      <dt>
       <span class="section">
        <a href="pluggable-storage-common-layer.html">
         18.11.2 The Common Database Server Layer
        </a>
       </span>
      </dt>
     </dl>
    </dd>
   </dl>
  </div>
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  </a>
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  </a>
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  <p>
   Storage engines are MySQL components that handle the SQL operations
    for different table types.
   <a class="link" href="innodb-storage-engine.html" title="Chapter 17 The InnoDB Storage Engine">
    <code class="literal">
     InnoDB
    </code>
   </a>
   is
    the default and most general-purpose storage engine, and Oracle
    recommends using it for tables except for specialized use cases.
    (The
   <a class="link" href="create-table.html" title="15.1.20 CREATE TABLE Statement">
    <code class="literal">
     CREATE TABLE
    </code>
   </a>
   statement in MySQL
    8.4 creates
   <code class="literal">
    InnoDB
   </code>
   tables by
    default.)
  </p>
  <p>
   MySQL Server uses a pluggable storage engine architecture that
    enables storage engines to be loaded into and unloaded from a
    running MySQL server.
  </p>
  <p>
   To determine which storage engines your server supports, use the
   <a class="link" href="show-engines.html" title="15.7.7.17 SHOW ENGINES Statement">
    <code class="literal">
     SHOW ENGINES
    </code>
   </a>
   statement. The value in
    the
   <code class="literal">
    Support
   </code>
   column indicates whether an engine
    can be used. A value of
   <code class="literal">
    YES
   </code>
   ,
   <code class="literal">
    NO
   </code>
   , or
   <code class="literal">
    DEFAULT
   </code>
   indicates that
    an engine is available, not available, or available and currently
    set as the default storage engine.
  </p>
  <div class="copytoclipboard-wrapper">
   <pre class="programlisting language-sql"><div class="docs-select-all right" id="sa43094108"><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 prompt">mysql&gt;</span> <span class="token keyword">SHOW</span> <span class="token keyword">ENGINES</span>\G
<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> 1. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
      Engine<span class="token punctuation">:</span> PERFORMANCE_SCHEMA
     Support<span class="token punctuation">:</span> YES
     Comment<span class="token punctuation">:</span> Performance Schema
Transactions<span class="token punctuation">:</span> NO
          XA<span class="token punctuation">:</span> NO
  Savepoints<span class="token punctuation">:</span> NO
<span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 2. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
      Engine<span class="token punctuation">:</span> InnoDB
     Support<span class="token punctuation">:</span> DEFAULT
     Comment<span class="token punctuation">:</span> Supports transactions, row-level locking, and foreign keys
Transactions<span class="token punctuation">:</span> YES
          XA<span class="token punctuation">:</span> YES
  Savepoints<span class="token punctuation">:</span> YES
<span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 3. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
      Engine<span class="token punctuation">:</span> MRG_MYISAM
     Support<span class="token punctuation">:</span> YES
     Comment<span class="token punctuation">:</span> Collection of identical MyISAM tables
Transactions<span class="token punctuation">:</span> NO
          XA<span class="token punctuation">:</span> NO
  Savepoints<span class="token punctuation">:</span> NO
<span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 4. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
      Engine<span class="token punctuation">:</span> BLACKHOLE
     Support<span class="token punctuation">:</span> YES
     Comment<span class="token punctuation">:</span> /dev/null storage engine (anything you write to it disappears)
Transactions<span class="token punctuation">:</span> NO
          XA<span class="token punctuation">:</span> NO
  Savepoints<span class="token punctuation">:</span> NO
<span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 5. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
      Engine<span class="token punctuation">:</span> MyISAM
     Support<span class="token punctuation">:</span> YES
     Comment<span class="token punctuation">:</span> MyISAM storage engine
Transactions<span class="token punctuation">:</span> NO
          XA<span class="token punctuation">:</span> NO
  Savepoints<span class="token punctuation">:</span> NO
...</span></code></pre>
  </div>
  <p>
   This chapter covers use cases for special-purpose MySQL storage
    engines. It does not cover the default
   <a class="link" href="innodb-storage-engine.html" title="Chapter 17 The InnoDB Storage Engine">
    <code class="literal">
     InnoDB
    </code>
   </a>
   storage engine or the
   <a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
    <code class="literal">
     NDB
    </code>
   </a>
   storage engine which are covered in
   <a class="xref" href="innodb-storage-engine.html" title="Chapter 17 The InnoDB Storage Engine">
    Chapter 17,
    <i>
     The InnoDB Storage Engine
    </i>
   </a>
   and
   <a class="xref" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
    Chapter 25,
    <i>
     MySQL NDB Cluster 8.4
    </i>
   </a>
   . For advanced users, it also
    contains a description of the pluggable storage engine architecture
    (see
   <a class="xref" href="pluggable-storage-overview.html" title="18.11 Overview of MySQL Storage Engine Architecture">
    Section 18.11, “Overview of MySQL Storage Engine Architecture”
   </a>
   ).
  </p>
  <p>
   For information about features offered in commercial MySQL Server
    binaries, see
   <a class="ulink" href="https://www.mysql.com/products/" target="_blank">
    <em class="citetitle">
     MySQL
    Editions
    </em>
   </a>
   , on the MySQL website. The storage
    engines available might depend on which edition of MySQL you are
    using.
  </p>
  <p>
   For answers to commonly asked questions about MySQL storage engines,
    see
   <a class="xref" href="faqs-storage-engines.html" title="A.2 MySQL 8.4 FAQ: Storage Engines">
    Section A.2, “MySQL 8.4 FAQ: Storage Engines”
   </a>
   .
  </p>
  <h2>
   <a name="idm46045148686400">
   </a>
   MySQL 8.4 Supported Storage Engines
  </h2>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      <a class="link" href="innodb-storage-engine.html" title="Chapter 17 The InnoDB Storage Engine">
       <code class="literal">
        InnoDB
       </code>
      </a>
      :
        The default storage engine in MySQL 8.4.
      <code class="literal">
       InnoDB
      </code>
      is a transaction-safe (ACID compliant)
        storage engine for MySQL that has commit, rollback, and
        crash-recovery capabilities to protect user data.
      <code class="literal">
       InnoDB
      </code>
      row-level locking (without escalation
        to coarser granularity locks) and Oracle-style consistent
        nonlocking reads increase multi-user concurrency and
        performance.
      <code class="literal">
       InnoDB
      </code>
      stores user data in
        clustered indexes to reduce I/O for common queries based on
        primary keys. To maintain data integrity,
      <code class="literal">
       InnoDB
      </code>
      also supports
      <code class="literal">
       FOREIGN
        KEY
      </code>
      referential-integrity constraints. For more
        information about
      <code class="literal">
       InnoDB
      </code>
      , see
      <a class="xref" href="innodb-storage-engine.html" title="Chapter 17 The InnoDB Storage Engine">
       Chapter 17,
       <i>
        The InnoDB Storage Engine
       </i>
      </a>
      .
     </p>
    </li>
    <li class="listitem">
     <p>
      <a class="link" href="myisam-storage-engine.html" title="18.2 The MyISAM Storage Engine">
       <code class="literal">
        MyISAM
       </code>
      </a>
      :
        These tables have a small footprint.
      <a class="link" href="glossary.html#glos_table_lock" title="table lock">
       Table-level locking
      </a>
      limits the performance in read/write workloads, so it is often
        used in read-only or read-mostly workloads in Web and data
        warehousing configurations.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a class="link" href="memory-storage-engine.html" title="18.3 The MEMORY Storage Engine">
       <code class="literal">
        Memory
       </code>
      </a>
      :
        Stores all data in RAM, for fast access in environments that
        require quick lookups of non-critical data. This engine was
        formerly known as the
      <code class="literal">
       HEAP
      </code>
      engine. Its use
        cases are decreasing;
      <code class="literal">
       InnoDB
      </code>
      with its buffer
        pool memory area provides a general-purpose and durable way to
        keep most or all data in memory, and
      <code class="literal">
       NDBCLUSTER
      </code>
      provides fast key-value lookups
        for huge distributed data sets.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a class="link" href="csv-storage-engine.html" title="18.4 The CSV Storage Engine">
       <code class="literal">
        CSV
       </code>
      </a>
      :
        Its tables are really text files with comma-separated values.
        CSV tables let you import or dump data in CSV format, to
        exchange data with scripts and applications that read and write
        that same format. Because CSV tables are not indexed, you
        typically keep the data in
      <code class="literal">
       InnoDB
      </code>
      tables
        during normal operation, and only use CSV tables during the
        import or export stage.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a class="link" href="archive-storage-engine.html" title="18.5 The ARCHIVE Storage Engine">
       <code class="literal">
        Archive
       </code>
      </a>
      :
        These compact, unindexed tables are intended for storing and
        retrieving large amounts of seldom-referenced historical,
        archived, or security audit information.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a class="link" href="blackhole-storage-engine.html" title="18.6 The BLACKHOLE Storage Engine">
       <code class="literal">
        Blackhole
       </code>
      </a>
      :
        The Blackhole storage engine accepts but does not store data,
        similar to the Unix
      <code class="literal">
       /dev/null
      </code>
      device. Queries
        always return an empty set. These tables can be used in
        replication configurations where DML statements are sent to
        replica servers, but the source server does not keep its own
        copy of the data.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
       <code class="literal">
        NDB
       </code>
      </a>
      (also known as
      <a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
       <code class="literal">
        NDBCLUSTER
       </code>
      </a>
      ): This clustered
        database engine is particularly suited for applications that
        require the highest possible degree of uptime and availability.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a class="link" href="merge-storage-engine.html" title="18.7 The MERGE Storage Engine">
       <code class="literal">
        Merge
       </code>
      </a>
      :
        Enables a MySQL DBA or developer to logically group a series of
        identical
      <code class="literal">
       MyISAM
      </code>
      tables and reference them as
        one object. Good for VLDB environments such as data warehousing.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a class="link" href="federated-storage-engine.html" title="18.8 The FEDERATED Storage Engine">
       <code class="literal">
        Federated
       </code>
      </a>
      :
        Offers the ability to link separate MySQL servers to create one
        logical database from many physical servers. Very good for
        distributed or data mart environments.
     </p>
    </li>
    <li class="listitem">
     <p>
      <a class="link" href="example-storage-engine.html" title="18.9 The EXAMPLE Storage Engine">
       <code class="literal">
        Example
       </code>
      </a>
      :
        This engine serves as an example in the MySQL source code that
        illustrates how to begin writing new storage engines. It is
        primarily of interest to developers. The storage engine is a
      <span class="quote">
       “
       <span class="quote">
        stub
       </span>
       ”
      </span>
      that does nothing. You can create tables
        with this engine, but no data can be stored in them or retrieved
        from them.
     </p>
    </li>
   </ul>
  </div>
  <p>
   You are not restricted to using the same storage engine for an
    entire server or schema. You can specify the storage engine for any
    table. For example, an application might use mostly
   <code class="literal">
    InnoDB
   </code>
   tables, with one
   <code class="literal">
    CSV
   </code>
   table for exporting data to a spreadsheet and a few
   <code class="literal">
    MEMORY
   </code>
   tables for temporary workspaces.
  </p>
  <p>
   <span class="bold">
    <strong>
     Choosing a Storage Engine
    </strong>
   </span>
  </p>
  <p>
   The various storage engines provided with MySQL are designed with
    different use cases in mind. The following table provides an
    overview of some storage engines provided with MySQL, with
    clarifying notes following the table.
  </p>
  <div class="table">
   <a name="idm46045148645968">
   </a>
   <p class="title">
    <b>
     Table 18.1 Storage Engines Feature Summary
    </b>
   </p>
   <div class="table-contents">
    <table frame="box" rules="all" summary="Summary of features supported per storage engine.">
     <colgroup>
      <col style="width: 10%"/>
      <col style="width: 16%"/>
      <col style="width: 16%"/>
      <col style="width: 16%"/>
      <col style="width: 16%"/>
      <col style="width: 16%"/>
     </colgroup>
     <thead>
      <tr>
       <th scope="col">
        Feature
       </th>
       <th scope="col">
        MyISAM
       </th>
       <th scope="col">
        Memory
       </th>
       <th scope="col">
        InnoDB
       </th>
       <th scope="col">
        Archive
       </th>
       <th scope="col">
        NDB
       </th>
      </tr>
     </thead>
     <tbody>
      <tr>
       <th scope="row">
        B-tree indexes
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        No
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        Backup/point-in-time recovery (note 1)
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        Cluster database support
       </th>
       <td>
        No
       </td>
       <td>
        No
       </td>
       <td>
        No
       </td>
       <td>
        No
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        Clustered indexes
       </th>
       <td>
        No
       </td>
       <td>
        No
       </td>
       <td>
        Yes
       </td>
       <td>
        No
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        Compressed data
       </th>
       <td>
        Yes (note 2)
       </td>
       <td>
        No
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        Data caches
       </th>
       <td>
        No
       </td>
       <td>
        N/A
       </td>
       <td>
        Yes
       </td>
       <td>
        No
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        Encrypted data
       </th>
       <td>
        Yes (note 3)
       </td>
       <td>
        Yes (note 3)
       </td>
       <td>
        Yes (note 4)
       </td>
       <td>
        Yes (note 3)
       </td>
       <td>
        Yes (note 5)
       </td>
      </tr>
      <tr>
       <th scope="row">
        Foreign key support
       </th>
       <td>
        No
       </td>
       <td>
        No
       </td>
       <td>
        Yes
       </td>
       <td>
        No
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        Full-text search indexes
       </th>
       <td>
        Yes
       </td>
       <td>
        No
       </td>
       <td>
        Yes (note 6)
       </td>
       <td>
        No
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        Geospatial data type support
       </th>
       <td>
        Yes
       </td>
       <td>
        No
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        Geospatial indexing support
       </th>
       <td>
        Yes
       </td>
       <td>
        No
       </td>
       <td>
        Yes (note 7)
       </td>
       <td>
        No
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        Hash indexes
       </th>
       <td>
        No
       </td>
       <td>
        Yes
       </td>
       <td>
        No (note 8)
       </td>
       <td>
        No
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        Index caches
       </th>
       <td>
        Yes
       </td>
       <td>
        N/A
       </td>
       <td>
        Yes
       </td>
       <td>
        No
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        Locking granularity
       </th>
       <td>
        Table
       </td>
       <td>
        Table
       </td>
       <td>
        Row
       </td>
       <td>
        Row
       </td>
       <td>
        Row
       </td>
      </tr>
      <tr>
       <th scope="row">
        MVCC
       </th>
       <td>
        No
       </td>
       <td>
        No
       </td>
       <td>
        Yes
       </td>
       <td>
        No
       </td>
       <td>
        No
       </td>
      </tr>
      <tr>
       <th scope="row">
        Replication support (note 1)
       </th>
       <td>
        Yes
       </td>
       <td>
        Limited (note 9)
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        Storage limits
       </th>
       <td>
        256TB
       </td>
       <td>
        RAM
       </td>
       <td>
        64TB
       </td>
       <td>
        None
       </td>
       <td>
        384EB
       </td>
      </tr>
      <tr>
       <th scope="row">
        T-tree indexes
       </th>
       <td>
        No
       </td>
       <td>
        No
       </td>
       <td>
        No
       </td>
       <td>
        No
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        Transactions
       </th>
       <td>
        No
       </td>
       <td>
        No
       </td>
       <td>
        Yes
       </td>
       <td>
        No
       </td>
       <td>
        Yes
       </td>
      </tr>
      <tr>
       <th scope="row">
        Update statistics for data dictionary
       </th>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
       <td>
        Yes
       </td>
      </tr>
     </tbody>
    </table>
   </div>
   <div class="table-contents">
    <table cellpadding="0" cellspacing="0" style="position: fixed; top: 0px; display: none; left: 401px; width: 739px;">
     <thead>
      <tr>
       <th scope="col" style="width: 112.359px;">
        Feature
       </th>
       <th scope="col" style="width: 125.125px;">
        MyISAM
       </th>
       <th scope="col" style="width: 125.125px;">
        Memory
       </th>
       <th scope="col" style="width: 125.125px;">
        InnoDB
       </th>
       <th scope="col" style="width: 125.125px;">
        Archive
       </th>
       <th scope="col" style="width: 125.141px;">
        NDB
       </th>
      </tr>
     </thead>
    </table>
   </div>
  </div>
  <br class="table-break"/>
  <p>
   <span class="bold">
    <strong>
     Notes:
    </strong>
   </span>
  </p>
  <p>
   1. Implemented in the server, rather than in the storage engine.
  </p>
  <p>
   2. Compressed MyISAM tables are supported only when using the compressed row format. Tables using the compressed row format with MyISAM are read only.
  </p>
  <p>
   3. Implemented in the server via encryption functions.
  </p>
  <p>
   4. Implemented in the server via encryption functions; In MySQL 5.7 and later, data-at-rest encryption is supported.
  </p>
  <p>
   5. Implemented in the server via encryption functions; encrypted NDB backups as of NDB 8.0.22; transparent NDB file system encryption supported in NDB 8.0.29 and later.
  </p>
  <p>
   6. Support for FULLTEXT indexes is available in MySQL 5.6 and later.
  </p>
  <p>
   7. Support for geospatial indexing is available in MySQL 5.7 and later.
  </p>
  <p>
   8. InnoDB utilizes hash indexes internally for its Adaptive Hash Index feature.
  </p>
  <p>
   9. See the discussion later in this section.
  </p>
 </div>
 <br/>
</div>
