Index: doc/src/sgml/config.sgml
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RCS file: /cvsroot/pgsql/doc/src/sgml/config.sgml,v
retrieving revision 1.307
diff -c -c -r1.307 config.sgml
*** doc/src/sgml/config.sgml	23 Aug 2010 02:43:25 -0000	1.307
--- doc/src/sgml/config.sgml	23 Aug 2010 18:55:02 -0000
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*** 4150,4161 ****
         <para>
          Specifies the maximum age (in transactions) that a table's
          <structname>pg_class</>.<structfield>relfrozenxid</> field can
!         attain before a <command>VACUUM</> operation is forced to allow removal
!         of old files from the <filename>pg_clog</> subdirectory and prevent
!         transaction ID wraparound within the table.  Note that the system
!         will launch autovacuum processes to prevent wraparound even when
!         autovacuum is otherwise disabled.
!         The default is 200 million transactions.
          This parameter can only be set at server start, but the setting
          can be reduced for individual tables by
          changing storage parameters.
--- 4150,4165 ----
         <para>
          Specifies the maximum age (in transactions) that a table's
          <structname>pg_class</>.<structfield>relfrozenxid</> field can
!         attain before a <command>VACUUM</> freeze operation is forced
!         to prevent transaction ID wraparound within the table.
!         Note that the system will launch autovacuum processes to
!         prevent wraparound even when autovacuum is otherwise disabled.
!        </para>
! 
!        <para>
!         Vacuum freeze also allows removal of old files from the
!         <filename>pg_clog</> subdirectory, which is why the default
!         is a relatively low 200 million transactions.
          This parameter can only be set at server start, but the setting
          can be reduced for individual tables by
          changing storage parameters.