relation targeted by the lock, or null if the target is not
       a relation or part of a relation
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>page</structfield> <type>int4</type>
      </para>
      <para>
       Page number targeted by the lock within the relation,
       or null if the target is not a relation page or tuple
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>tuple</structfield> <type>int2</type>
      </para>
      <para>
       Tuple number targeted by the lock within the page,
       or null if the target is not a tuple
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>virtualxid</structfield> <type>text</type>
      </para>
      <para>
       Virtual ID of the transaction targeted by the lock,
       or null if the target is not a virtual transaction ID;  see
       <xref linkend="transactions"/>
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>transactionid</structfield> <type>xid</type>
      </para>
      <para>
       ID of the transaction targeted by the lock, or null if the target
       is not a transaction ID;  <xref linkend="transactions"/>
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>classid</structfield> <type>oid</type>
       (references <link linkend="catalog-pg-class"><structname>pg_class</structname></link>.<structfield>oid</structfield>)
      </para>
      <para>
       OID of the system catalog containing the lock target, or null if the
       target is not a general database object
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>objid</structfield> <type>oid</type>
       (references any OID column)
      </para>
      <para>
       OID of the lock target within its system catalog, or null if the
       target is not a general database object
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>objsubid</structfield> <type>int2</type>
      </para>
      <para>
       Column number targeted by the lock (the
       <structfield>classid</structfield> and <structfield>objid</structfield> refer to the
       table itself),
       or zero if the target is some other general database object,
       or null if the target is not a general database object
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>virtualtransaction</structfield> <type>text</type>
      </para>
      <para>
       Virtual ID of the transaction that is holding or awaiting this lock
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>pid</structfield> <type>int4</type>
      </para>
      <para>
       Process ID of the server process holding or awaiting this
       lock, or null if the lock is held by a prepared transaction
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>mode</structfield> <type>text</type>
      </para>
      <para>
       Name of the lock mode held or desired by this process (see <xref linkend="locking-tables"/> and <xref linkend="xact-serializable"/>)
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
       <structfield>granted</structfield> <type>bool</type>
      </para>
      <para>
       True if lock is held, false if lock is awaited
      </para></entry>