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Improve recovery target settings documentation.

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Commit 815d71dee hadn't bothered to update the documentation to match the
behavioral change, and a lot of other text in this section was badly in
need of copy-editing.
This commit is contained in:
Tom Lane 2014-12-13 13:46:44 -05:00
parent b0f479113a
commit e311cd6ded
1 changed files with 49 additions and 45 deletions
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doc/src/sgml/recovery-config.sgml
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@ -152,16 +152,18 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows
<sect1 id="recovery-target-settings"> <sect1 id="recovery-target-settings">
<title>Recovery Target Settings</title> <title>Recovery Target Settings</title>
<para> <para>
By default, recovery will recover to the end of the WAL log. The By default, recovery will recover to the end of the WAL log. The
following parameters can be used to specify an earlier stopping point. following parameters can be used to specify an earlier stopping point.
At most one of <varname>recovery_target</>, At most one of <varname>recovery_target</>,
<varname>recovery_target_name</>, <varname>recovery_target_time</>, or <varname>recovery_target_name</>, <varname>recovery_target_time</>, or
<varname>recovery_target_xid</> can be specified. <varname>recovery_target_xid</> can be used; if more than one of these
is specified in the configuration file, the last entry will be used.
</para> </para>
<variablelist>
<varlistentry id="recovery-target" xreflabel="recovery_target_name"> <variablelist>
<varlistentry id="recovery-target" xreflabel="recovery_target">
<term><varname>recovery_target</varname><literal> = 'immediate'</literal> <term><varname>recovery_target</varname><literal> = 'immediate'</literal>
<indexterm> <indexterm>
<primary><varname>recovery_target</> recovery parameter</primary> <primary><varname>recovery_target</> recovery parameter</primary>
@ -189,8 +191,8 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows
</term> </term>
<listitem> <listitem>
<para> <para>
This parameter specifies the named restore point, created with This parameter specifies the named restore point (created with
<function>pg_create_restore_point()</> to which recovery will proceed. <function>pg_create_restore_point()</>) to which recovery will proceed.
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
@ -231,13 +233,13 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows
</listitem> </listitem>
</varlistentry> </varlistentry>
</variablelist> </variablelist>
<para> <para>
The following options further specify the recovery target, and affect The following options further specify the recovery target, and affect
what happens when the target is reached: what happens when the target is reached:
</para> </para>
<variablelist> <variablelist>
<varlistentry id="recovery-target-inclusive" <varlistentry id="recovery-target-inclusive"
xreflabel="recovery_target_inclusive"> xreflabel="recovery_target_inclusive">
<term><varname>recovery_target_inclusive</varname> (<type>boolean</type>) <term><varname>recovery_target_inclusive</varname> (<type>boolean</type>)
@ -247,12 +249,12 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows
</term> </term>
<listitem> <listitem>
<para> <para>
Specifies whether we stop just after the specified recovery target Specifies whether to stop just after the specified recovery target
(<literal>true</literal>), or just before the recovery target (<literal>true</literal>), or just before the recovery target
(<literal>false</literal>). (<literal>false</literal>).
Applies to both <xref linkend="recovery-target-time"> Applies when either <xref linkend="recovery-target-time">
and <xref linkend="recovery-target-xid">, whichever one is or <xref linkend="recovery-target-xid"> is specified.
specified for this recovery. This indicates whether transactions This setting controls whether transactions
having exactly the target commit time or ID, respectively, will having exactly the target commit time or ID, respectively, will
be included in the recovery. Default is <literal>true</>. be included in the recovery. Default is <literal>true</>.
</para> </para>
@ -280,27 +282,7 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows
</listitem> </listitem>
</varlistentry> </varlistentry>
<varlistentry id="pause-at-recovery-target" <varlistentry id="recovery-target-action"
xreflabel="pause_at_recovery_target">
<term><varname>pause_at_recovery_target</varname> (<type>boolean</type>)
<indexterm>
<primary><varname>pause_at_recovery_target</> recovery parameter</primary>
</indexterm>
</term>
<listitem>
<para>
Alias for recovery_target_action, <literal>true</> is same as
recovery_target_action = <literal>pause</> and <literal>false</>
is same as recovery_target_action = <literal>promote</>.
</para>
<para>
This setting has no effect if <xref linkend="guc-hot-standby"> is not
enabled, or if no recovery target is set.
</para>
</listitem>
</varlistentry>
<varlistentry id="action-at-recovery-target"
xreflabel="recovery_target_action"> xreflabel="recovery_target_action">
<term><varname>recovery_target_action</varname> (<type>enum</type>) <term><varname>recovery_target_action</varname> (<type>enum</type>)
<indexterm> <indexterm>
@ -311,35 +293,35 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows
<para> <para>
Specifies what action the server should take once the recovery target is Specifies what action the server should take once the recovery target is
reached. The default is <literal>pause</>, which means recovery will reached. The default is <literal>pause</>, which means recovery will
be paused. <literal>promote</> means recovery process will finish and be paused. <literal>promote</> means the recovery process will finish
the server will start to accept connections. and the server will start to accept connections.
Finally <literal>shutdown</> will stop the server after reaching the Finally <literal>shutdown</> will stop the server after reaching the
recovery target. recovery target.
</para> </para>
<para> <para>
The intended use of <literal>pause</> setting is to allow queries to be The intended use of the <literal>pause</> setting is to allow queries
executed against the database to check if this recovery target is the to be executed against the database to check if this recovery target
most desirable point for recovery. The paused state can be resumed by is the most desirable point for recovery.
using <function>pg_xlog_replay_resume()</> (See The paused state can be resumed by
using <function>pg_xlog_replay_resume()</> (see
<xref linkend="functions-recovery-control-table">), which then <xref linkend="functions-recovery-control-table">), which then
causes recovery to end. If this recovery target is not the causes recovery to end. If this recovery target is not the
desired stopping point, then shutdown the server, change the desired stopping point, then shut down the server, change the
recovery target settings to a later target and restart to recovery target settings to a later target and restart to
continue recovery. continue recovery.
</para> </para>
<para> <para>
The <literal>shutdown</> setting is useful to have instance ready at The <literal>shutdown</> setting is useful to have the instance ready
exact replay point desired. at the exact replay point desired. The instance will still be able to
The instance will still be able to replay more WAL records (and in fact replay more WAL records (and in fact will have to replay WAL records
will have to replay WAL records since last checkpoint next time it is since the last checkpoint next time it is started).
started).
</para> </para>
<para> <para>
Note that because <filename>recovery.conf</> will not be renamed when Note that because <filename>recovery.conf</> will not be renamed when
<varname>recovery_target_action</> is set to <literal>shutdown</>, <varname>recovery_target_action</> is set to <literal>shutdown</>,
any subsequent start will end with immediate shutdown unless the any subsequent start will end with immediate shutdown unless the
configuration is changed or the <filename>recovery.conf</> is removed configuration is changed or the <filename>recovery.conf</> file is
manually. removed manually.
</para> </para>
<para> <para>
This setting has no effect if no recovery target is set. This setting has no effect if no recovery target is set.
@ -349,6 +331,28 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows
</listitem> </listitem>
</varlistentry> </varlistentry>
<varlistentry id="pause-at-recovery-target"
xreflabel="pause_at_recovery_target">
<term><varname>pause_at_recovery_target</varname> (<type>boolean</type>)
<indexterm>
<primary><varname>pause_at_recovery_target</> recovery parameter</primary>
</indexterm>
</term>
<listitem>
<para>
This is an obsolete version of <varname>recovery_target_action</>.
Setting it to <literal>true</> is the same as
<varname>recovery_target_action</> = <literal>pause</>,
while <literal>false</> is the same as
<varname>recovery_target_action</> = <literal>promote</>.
</para>
<para>
This setting has no effect if <xref linkend="guc-hot-standby"> is not
enabled, or if no recovery target is set.
</para>
</listitem>
</varlistentry>
</variablelist> </variablelist>
</sect1> </sect1>