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     <h4 class="title">
      <a name="mysql-cluster-limitations-database-objects">
      </a>
      25.2.7.5 Limits Associated with Database Objects in NDB Cluster
     </h4>
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   </div>
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  <a class="indexterm" name="idm46045123311728">
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  <p>
   Some database objects such as tables and indexes have different
        limitations when using the
   <a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
    <code class="literal">
     NDBCLUSTER
    </code>
   </a>
   storage engine:
  </p>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      <b>
       Number of database objects.
      </b>
      The maximum number of
      <span class="emphasis">
       <em>
        all
       </em>
      </span>
      <a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
       <code class="literal">
        NDB
       </code>
      </a>
      database objects in a
              single NDB Cluster—including databases, tables, and
              indexes—is limited to 20320.
     </p>
    </li>
    <li class="listitem">
     <p>
      <b>
       Attributes per table.
      </b>
      The maximum number of attributes (that is, columns and
              indexes) that can belong to a given table is 512.
     </p>
    </li>
    <li class="listitem">
     <p>
      <b>
       Attributes per key.
      </b>
      The maximum number of attributes per key is 32.
     </p>
    </li>
    <li class="listitem">
     <p>
      <b>
       Row size.
      </b>
      The maximum permitted size of any one row is 30000 bytes.
     </p>
     <p>
      Each
      <a class="link" href="blob.html" title="13.3.4 The BLOB and TEXT Types">
       <code class="literal">
        BLOB
       </code>
      </a>
      or
      <a class="link" href="blob.html" title="13.3.4 The BLOB and TEXT Types">
       <code class="literal">
        TEXT
       </code>
      </a>
      column contributes 256 +
            8 = 264 bytes to this total; this includes
      <a class="link" href="json.html" title="13.5 The JSON Data Type">
       <code class="literal">
        JSON
       </code>
      </a>
      columns. See
      <a class="xref" href="storage-requirements.html#data-types-storage-reqs-strings" title="String Type Storage Requirements">
       String Type Storage Requirements
      </a>
      , as well
            as
      <a class="xref" href="storage-requirements.html#data-types-storage-reqs-json" title="JSON Storage Requirements">
       JSON Storage Requirements
      </a>
      , for more
            information relating to these types.
     </p>
     <p>
      In addition, the maximum offset for a fixed-width column of
            an
      <code class="literal">
       NDB
      </code>
      table is 8188 bytes; attempting to
            create a table that violates this limitation fails with NDB
            error 851
      <span class="errortext">
       Maximum offset for fixed-size columns
            exceeded
      </span>
      . For memory-based columns, you can work
            around this limitation by using a variable-width column type
            such as
      <a class="link" href="char.html" title="13.3.2 The CHAR and VARCHAR Types">
       <code class="literal">
        VARCHAR
       </code>
      </a>
      or defining
            the column as
      <code class="literal">
       COLUMN_FORMAT=DYNAMIC
      </code>
      ; this
            does not work with columns stored on disk. For disk-based
            columns, you may be able to do so by reordering one or more
            of the table's disk-based columns such that the
            combined width of all but the disk-based column defined last
            in the
      <a class="link" href="create-table.html" title="15.1.20 CREATE TABLE Statement">
       <code class="literal">
        CREATE TABLE
       </code>
      </a>
      statement
            used to create the table does not exceed 8188 bytes, less
            any possible rounding performed for some data types such as
      <a class="link" href="char.html" title="13.3.2 The CHAR and VARCHAR Types">
       <code class="literal">
        CHAR
       </code>
      </a>
      or
      <code class="literal">
       VARCHAR
      </code>
      ; otherwise it is necessary to use
            memory-based storage for one or more of the offending column
            or columns instead.
     </p>
    </li>
    <li class="listitem">
     <p>
      <b>
       BIT column storage per table.
      </b>
      The maximum combined width for all
      <a class="link" href="bit-type.html" title="13.1.5 Bit-Value Type - BIT">
       <code class="literal">
        BIT
       </code>
      </a>
      columns used in a given
      <code class="literal">
       NDB
      </code>
      table is 4096.
     </p>
    </li>
    <li class="listitem">
     <p>
      <b>
       FIXED column storage.
      </b>
      NDB Cluster supports a maximum of 128 TB per fragment of
              data in
      <code class="literal">
       FIXED
      </code>
      columns.
     </p>
    </li>
   </ul>
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