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A few improvements to analyze and vacuum sections in documentation: add "see

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also" entries for autovacuum in analyze and vacuum reference pages, and
enhance usage of cross-references in the maintenance page.
This commit is contained in:
Alvaro Herrera 2007-10-07 01:16:42 +00:00
parent a3ff937359
commit 2a997a7065
3 changed files with 35 additions and 14 deletions
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24
doc/src/sgml/maintenance.sgml
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@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/maintenance.sgml,v 1.83 2007/10/06 17:45:49 alvherre Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/maintenance.sgml,v 1.84 2007/10/07 01:16:42 alvherre Exp $ -->
<chapter id="maintenance">
<title>Routine Database Maintenance Tasks</title>
@ -59,9 +59,9 @@
</indexterm>
<para>
<productname>PostgreSQL</productname>'s <command>VACUUM</> (<xref
linkend="sql-vacuum">) command has to run on a regular basis for several
reasons:
<productname>PostgreSQL</productname>'s
<xref linkend="sql-vacuum" endterm="sql-vacuum-title"> command has to run on
a regular basis for several reasons:
<orderedlist>
<listitem>
@ -96,7 +96,8 @@
</para>
<para>
Fortunately, autovacuum (<xref linkend="autovacuum">) monitors table
Fortunately, <xref linkend="autovacuum" endterm="autovacuum-title">
monitors table
activity and performs <command>VACUUM</command>s when necessary.
Autovacuum works dynamically so it is often better
administration-scheduled vacuuming.
@ -150,7 +151,8 @@
</para>
<para>
Fortunately, autovacuum (<xref linkend="autovacuum">) monitors table
Fortunately, <xref linkend="autovacuum" endterm="autovacuum-title">
monitors table
activity and performs <command>VACUUM</command>s when necessary. This
eliminates the need for administrators to worry about disk space
recovery in all but the most unusual cases.
@ -218,7 +220,8 @@
The <productname>PostgreSQL</productname> query planner relies on
statistical information about the contents of tables in order to
generate good plans for queries. These statistics are gathered by
the <command>ANALYZE</> command, which can be invoked by itself or
the <xref linkend="sql-analyze" endterm="sql-analyze-title"> command,
which can be invoked by itself or
as an optional step in <command>VACUUM</>. It is important to have
reasonably accurate statistics, otherwise poor choices of plans might
degrade database performance.
@ -262,7 +265,8 @@
</tip>
<para>
Fortunately, autovacuum (<xref linkend="autovacuum">) monitors table
Fortunately, <xref linkend="autovacuum" endterm="autovacuum-title">
monitors table
activity and performs <command>ANALYZE</command>s when necessary. This
eliminates the need for administrators to manually schedule
<command>ANALYZE</command>.
@ -341,8 +345,8 @@
when it was last vacuumed.
If it were to go unvacuumed for longer than that,
data loss could result. To ensure that this does not
happen, the <firstterm>autovacuum</> facility described in
<xref linkend="autovacuum"> is invoked on any table
happen, <xref linkend="autovacuum" endterm="autovacuum-title">
is invoked on any table
that might contain XIDs older than the age specified by the
configuration parameter
<xref linkend="guc-autovacuum-freeze-max-age">. (This will happen

22
doc/src/sgml/ref/analyze.sgml
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@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/analyze.sgml,v 1.22 2007/05/15 19:13:55 neilc Exp $
$PostgreSQL: pgsql/doc/src/sgml/ref/analyze.sgml,v 1.23 2007/10/07 01:16:42 alvherre Exp $
PostgreSQL documentation
-->
@ -92,7 +92,12 @@ ANALYZE [ VERBOSE ] [ <replaceable class="PARAMETER">table</replaceable> [ ( <re
<title>Notes</title>
<para>
It is a good idea to run <command>ANALYZE</command> periodically, or
In the default <productname>PostgreSQL</productname> configuration,
<xref linkend="autovacuum" endterm="autovacuum-title">
takes care of automatic analyzing of tables when they are first loaded
with data, and as they change throughout regular operation.
When autovacuum is disabled,
it is a good idea to run <command>ANALYZE</command> periodically, or
just after making major changes in the contents of a table. Accurate
statistics will help the planner to choose the most appropriate query
plan, and thereby improve the speed of query processing. A common
@ -101,7 +106,7 @@ ANALYZE [ VERBOSE ] [ <replaceable class="PARAMETER">table</replaceable> [ ( <re
</para>
<para>
Unlike <command>VACUUM FULL</command>, <command>ANALYZE</command>
<command>ANALYZE</command>
requires only a read lock on the target table, so it can run in
parallel with other activity on the table.
</para>
@ -168,4 +173,15 @@ ANALYZE [ VERBOSE ] [ <replaceable class="PARAMETER">table</replaceable> [ ( <re
There is no <command>ANALYZE</command> statement in the SQL standard.
</para>
</refsect1>
<refsect1>
<title>See Also</title>
<simplelist type="inline">
<member><xref linkend="sql-vacuum" endterm="sql-vacuum-title"></member>
<member><xref linkend="app-vacuumdb" endterm="app-vacuumdb-title"></member>
<member><xref linkend="runtime-config-resource-vacuum-cost" endterm="runtime-config-resource-vacuum-cost-title"></member>
<member><xref linkend="autovacuum" endterm="autovacuum-title"></member>
</simplelist>
</refsect1>
</refentry>

3
doc/src/sgml/ref/vacuum.sgml
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@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/vacuum.sgml,v 1.48 2007/05/30 19:45:01 momjian Exp $
$PostgreSQL: pgsql/doc/src/sgml/ref/vacuum.sgml,v 1.49 2007/10/07 01:16:42 alvherre Exp $
PostgreSQL documentation
-->
@ -242,6 +242,7 @@ VACUUM
<simplelist type="inline">
<member><xref linkend="app-vacuumdb" endterm="app-vacuumdb-title"></member>
<member><xref linkend="runtime-config-resource-vacuum-cost" endterm="runtime-config-resource-vacuum-cost-title"></member>
<member><xref linkend="autovacuum" endterm="autovacuum-title"></member>
</simplelist>
</refsect1>
</refentry>