diff --git a/doc/src/sgml/pgbuffercache.sgml b/doc/src/sgml/pgbuffercache.sgml
new file mode 100644
index 1d7d95f..60e45e0
*** a/doc/src/sgml/pgbuffercache.sgml
--- b/doc/src/sgml/pgbuffercache.sgml
***************
*** 74,90 ****
       </row>
  
       <row>
!       <entry><structfield>relblocknumber</structfield></entry>
!       <entry><type>bigint</type></entry>
        <entry></entry>
!       <entry>Page number within the relation</entry>
       </row>
  
       <row>
!       <entry><structfield>relforknumber</structfield></entry>
!       <entry><type>smallint</type></entry>
        <entry></entry>
!       <entry>Fork number within the relation</entry>
       </row>
  
       <row>
--- 74,90 ----
       </row>
  
       <row>
!       <entry><structfield>relforknumber</structfield></entry>
!       <entry><type>smallint</type></entry>
        <entry></entry>
!       <entry>Fork number within the relation. Main table: 0; Free Space Map: 1; Visibility Map: 2; Init fork: 3</entry>
       </row>
  
       <row>
!       <entry><structfield>relblocknumber</structfield></entry>
!       <entry><type>bigint</type></entry>
        <entry></entry>
!       <entry>Page number within the relation</entry>
       </row>
  
       <row>