Index: catalogs.sgml
===================================================================
RCS file: /home/alvherre/cvs/pgsql/doc/src/sgml/catalogs.sgml,v
retrieving revision 2.113
diff -c -r2.113 catalogs.sgml
*** catalogs.sgml	8 Sep 2005 20:07:41 -0000	2.113
--- catalogs.sgml	12 Sep 2005 13:56:35 -0000
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*** 1137,1145 ****
     <primary>pg_autovacuum</primary>
    </indexterm>
  
    <para>
     The catalog <structname>pg_autovacuum</structname> stores optional
!    per-relation configuration parameters for <quote>autovacuum</>.
     If there is an entry here for a particular relation, the given
     parameters will be used for autovacuuming that table.  If no entry
     is present, the system-wide defaults will be used.
--- 1137,1150 ----
     <primary>pg_autovacuum</primary>
    </indexterm>
  
+   <indexterm zone="catalog-pg-autovacuum">
+    <primary>autovacuum</primary>
+    <secondary>table-specific configuration</secondary>
+   </indexterm>
+ 
    <para>
     The catalog <structname>pg_autovacuum</structname> stores optional
!    per-relation configuration parameters for <xref linkend="autovacuum" endterm="autovacuum-title">.
     If there is an entry here for a particular relation, the given
     parameters will be used for autovacuuming that table.  If no entry
     is present, the system-wide defaults will be used.
Index: maintenance.sgml
===================================================================
RCS file: /home/alvherre/cvs/pgsql/doc/src/sgml/maintenance.sgml,v
retrieving revision 1.45
diff -c -r1.45 maintenance.sgml
*** maintenance.sgml	22 Jun 2005 21:14:28 -0000	1.45
--- maintenance.sgml	12 Sep 2005 14:10:17 -0000
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*** 99,104 ****
--- 99,110 ----
     <xref linkend="runtime-config-resource-vacuum-cost">.
    </para>
  
+   <para>
+    An automated mechanism for performing the necessary <command>VACUUM</>
+    operations has been added in <productname>PostgreSQL</productname> 8.1.
+    See <xref linkend="autovacuum" endterm="autovacuum-title">.
+   </para>
+ 
    <sect2 id="vacuum-for-space-recovery">
     <title>Recovering disk space</title>
  
***************
*** 177,189 ****
      the program <filename>vacuumdb</> may be helpful.
     </para>
  
-    <tip>
-     <para>
-      The <filename>contrib/pg_autovacuum</> program can be useful for
-      automating high-frequency vacuuming operations.
-     </para>
-    </tip>
- 
     <para>
      <command>VACUUM FULL</> is recommended for cases where you know
      you have deleted the majority of rows in a table, so that the
--- 183,188 ----
***************
*** 456,461 ****
--- 455,551 ----
      </para>
     </warning>
    </sect2>
+ 
+   <sect2 id="autovacuum">
+    <title id="autovacuum-title">The Auto-Vacuum Daemon</title>
+ 
+    <indexterm>
+     <primary>autovacuum</primary>
+     <secondary>general information</secondary>
+    </indexterm>
+    <para>
+     Beginning in <productname>PostgreSQL </productname> 8.1, there is a
+     separate optional server process called the <firstterm>autovacuum
+     daemon</firstterm>, whose purpose is to automate the issuance of
+     <command>VACUUM</command> and <command>ANALYZE </command> commands.
+     When enabled, the autovacuum daemon runs periodically and checks for
+     tables that have had a large number of inserted, updated or deleted
+     tuples.  These checks use the row-level statistics collection facility;
+     therefore, the autovacuum daemon cannot be used unless <xref
+     linkend="guc-stats-start-collector"> and <xref
+     linkend="guc-stats-row-level"> are set <literal>true</literal>.  Also, it's
+     important to allow a slot for the autovacuum process when choosing the
+     value of <xref linkend="guc-superuser-reserved-connections">.
+    </para>
+ 
+    <para>
+     The autovacuum daemon, when enabled, runs every <xref
+     linkend="guc-autovacuum-naptime"> seconds and determines which database
+     to process.  Any database which is close to transaction ID wraparound
+     is immediately processed.  In this case, autovacuum issues a
+     database-wide <command>VACUUM</command> call, or <command>VACUUM
+     FREEZE</command> if it's a template database, and then terminates.  If
+     no database fulfills this criterion, the one that was least recently
+     processed by autovacuum itself is chosen.  In this mode, each table in
+     the database is checked for new and obsolete tuples, according to the
+     applicable autovacuum parameters.  If a <link linkend="catalog-pg-autovacuum">
+     <structname>pg_autovacuum</structname></link> tuple is found for this
+     table, these settings are applied; otherwise the global values in
+     <filename>postgresql.conf</filename> are used.  See <xref linkend="runtime-config-autovacuum">
+     for more details on the global settings.  Note that the autovacuum
+     daemon can be instructed to skip particular tables, by setting the
+     <structname>pg_autovacuum</>.<structfield>enabled</> field to <literal>false</literal>.
+    </para>
+ 
+    <para>
+     For each table, two conditions are used to determine which operation to
+     apply.  If the number of obsolete tuples since the last
+     <command>VACUUM</command> exceeds the <quote>vacuum threshold</quote>, the
+     table is vacuumed and analyzed.  The vacuum threshold is defined as:
+ <programlisting>
+ vacuum threshold = vacuum base threshold + vacuum scale factor * number of tuples
+ </programlisting>
+     where the vacuum base threshold is
+     <structname>pg_autovacuum</structname>.<structfield>vac_base_thresh</structfield>,
+     the vacuum scale factor is
+     <structname>pg_autovacuum</structname>.<structfield>vac_scale_factor</structfield>
+     and the number of tuples is
+     <structname>pg_class</structname>.<structfield>reltuples</structfield>.
+     The number of obsolete tuples is taken from the statistics
+     collector, which is a semi-accurate count updated by each
+     <command>UPDATE</command> and <command>DELETE</command> operation.  (It
+     is only semi-accurate because some information may be lost under heavy
+     load.)  For analyze, a similar condition is used: the threshold, calculated
+     by an equivalent equation to that above, is compared to the number of
+     new tuples, that is, those created by the <command>INSERT</command> and
+     <command>COPY</command> commands.
+    </para>
+ 
+    <para>
+     Note that if any of the values in <structname>pg_autovacuum</structname>
+     is set to a negative number, or if a tuple is not present at all in
+     <structname>pg_autovacuum</structname> for any particular table, the
+     equivalent value from <filename>postgresql.conf</filename> is used.
+    </para>
+ 
+    <para>
+     Additionally to the base threshold values and scale factors, there are
+     two parameters that can be set for each table in <structname>pg_autovacuum</structname>: 
+     the vacuum cost delay
+     (<structname>pg_autovacuum</structname>.<structfield>vac_cost_delay</structfield>)
+     and the vacuum cost limit
+     (<structname>pg_autovacuum</structname>.<structfield>vac_cost_limit</structfield>).
+     They are used to set table-specific values for the
+     <xref linkend="runtime-config-resource-vacuum-cost" endterm="runtime-config-resource-vacuum-cost-title">
+     feature.  The above note about negative values also applies here, but
+     also note that if the <filename>postgresql.conf</filename> variables
+     <varname>autovacuum_vacuum_cost_limit</varname> and
+     <varname>autovacuum_vacuum_cost_delay</varname> are also set to negative 
+     values, the <varname>vacuum_cost_limit</varname> and
+     <varname>vacuum_cost_delay</varname> values will be used instead.
+    </para>
+ 
+   </sect2>
   </sect1>
  
  
Index: runtime.sgml
===================================================================
RCS file: /home/alvherre/cvs/pgsql/doc/src/sgml/runtime.sgml,v
retrieving revision 1.352
diff -c -r1.352 runtime.sgml
*** runtime.sgml	30 Aug 2005 15:48:28 -0000	1.352
--- runtime.sgml	12 Sep 2005 13:55:25 -0000
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*** 3344,3361 ****
     <sect2 id="runtime-config-autovacuum">
      <title>Automatic Vacuuming</title>
  
       <para>
!       Beginning in <productname>PostgreSQL</> 8.1, there is an optional server
!       process called the <firstterm>autovacuum daemon</>, whose purpose is
!       to automate the issuance of periodic <command>VACUUM</> and
!       <command>ANALYZE</> commands.  When enabled, the autovacuum daemon
!       runs periodically and checks for tables that have had a large number
!       of updated or deleted tuples.  This check uses the row-level statistics
!       collection facility; therefore, the autovacuum daemon cannot be used
!       unless <xref linkend="guc-stats-start-collector"> and
!       <xref linkend="guc-stats-row-level"> are set TRUE.  Also, it's
!       important to allow a slot for the autovacuum process when choosing
!       the value of <xref linkend="guc-superuser-reserved-connections">.
       </para>
  
      <variablelist>
--- 3344,3358 ----
     <sect2 id="runtime-config-autovacuum">
      <title>Automatic Vacuuming</title>
  
+     <indexterm>
+      <primary>autovacuum</primary>
+      <secondary>global configuration parameters</secondary>
+     </indexterm>
+ 
       <para>
!       These settings control the default behavior for the <firstterm>autovacuum
!       daemon</firstterm>. Please refer to <xref linkend="autovacuum"> for
!       more information.
       </para>
  
      <variablelist>
***************
*** 3470,3477 ****
          <command>VACUUM</> operations.  If -1 is specified (which is the
          default), the regular
          <xref linkend="guc-vacuum-cost-delay"> value will be used.
-         This setting can be overridden for individual tables by entries in
-         <structname>pg_autovacuum</>.
         </para>
        </listitem>
       </varlistentry>
--- 3467,3472 ----
***************
*** 3487,3494 ****
          <command>VACUUM</> operations.  If -1 is specified (which is the
          default), the regular
          <xref linkend="guc-vacuum-cost-limit"> value will be used.
-         This setting can be overridden for individual tables by entries in
-         <structname>pg_autovacuum</>.
         </para>
        </listitem>
       </varlistentry>
--- 3482,3487 ----