mirror of https://github.com/postgres/postgres
They used to be scattered between the "backup and restore" and "streaming replication" chapters.REL9_0_ALPHA5_BRANCH
Heikki Linnakangas
16 years ago
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<!-- $PostgreSQL: pgsql/doc/src/sgml/recovery-config.sgml,v 2.1 2010/02/22 11:47:30 heikki Exp $ --> |
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<chapter Id="recovery-config"> |
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<title>Recovery Configuration</title> |
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<indexterm> |
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<primary>configuration</primary> |
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<secondary>of recovery</secondary> |
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<tertiary>of a standby server</tertiary> |
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</indexterm> |
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<para> |
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This chapter describes the settings available in |
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<filename>recovery.conf</> file. They apply only for the duration of |
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the recovery. (A sample file, <filename>share/recovery.conf.sample</>, |
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exists in the installation's <filename>share/</> directory.) They must |
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be reset for any subsequent recovery you wish to perform. They cannot |
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be changed once recovery has begun. |
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</para> |
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<sect1 id="archive-recovery-settings"> |
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<title>Archive recovery settings</title> |
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<variablelist> |
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<varlistentry id="restore-command" xreflabel="restore_command"> |
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<term><varname>restore_command</varname> (<type>string</type>)</term> |
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<listitem> |
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<para> |
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The shell command to execute to retrieve an archived segment of |
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the WAL file series. This parameter is required for archive recovery, |
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but optional for streaming replication. |
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Any <literal>%f</> in the string is |
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replaced by the name of the file to retrieve from the archive, |
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and any <literal>%p</> is replaced by the copy destination path name |
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on the server. |
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(The path name is relative to the current working directory, |
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i.e., the cluster's data directory.) |
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Any <literal>%r</> is replaced by the name of the file containing the |
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last valid restart point. That is the earliest file that must be kept |
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to allow a restore to be restartable, so this information can be used |
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to truncate the archive to just the minimum required to support |
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restarting from the current restore. <literal>%r</> is typically only |
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used by warm-standby configurations |
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(see <xref linkend="warm-standby">). |
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Write <literal>%%</> to embed an actual <literal>%</> character. |
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</para> |
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|
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<para> |
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It is important for the command to return a zero exit status |
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only if it succeeds. The command <emphasis>will</> be asked for file |
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names that are not present in the archive; it must return nonzero |
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when so asked. Examples: |
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<programlisting> |
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restore_command = 'cp /mnt/server/archivedir/%f "%p"' |
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restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows |
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</programlisting> |
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</para> |
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</listitem> |
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</varlistentry> |
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|
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<varlistentry id="recovery-end-command" xreflabel="recovery_end_command"> |
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<term><varname>recovery_end_command</varname> (<type>string</type>)</term> |
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<listitem> |
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<para> |
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This parameter specifies a shell command that will be executed once only |
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at the end of recovery. This parameter is optional. The purpose of the |
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<varname>recovery_end_command</> is to provide a mechanism for cleanup |
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following replication or recovery. |
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Any <literal>%r</> is replaced by the name of the file |
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containing the last valid restart point. That is the earliest file that |
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must be kept to allow a restore to be restartable, so this information |
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can be used to truncate the archive to just the minimum required to |
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support restart from the current restore. <literal>%r</> would |
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typically be used in a warm-standby configuration |
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(see <xref linkend="warm-standby">). |
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Write <literal>%%</> to embed an actual <literal>%</> character |
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in the command. |
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</para> |
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<para> |
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If the command returns a non-zero exit status then a WARNING log |
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message will be written and the database will proceed to start up |
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anyway. An exception is that if the command was terminated by a |
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signal, the database will not proceed with startup. |
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</para> |
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</listitem> |
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</varlistentry> |
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|
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</variablelist> |
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</sect1> |
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<sect1 id="recovery-target-settings"> |
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<title>Recovery target settings</title> |
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<variablelist> |
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<varlistentry id="recovery-target-time" xreflabel="recovery_target_time"> |
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<term><varname>recovery_target_time</varname> |
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(<type>timestamp</type>) |
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</term> |
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<listitem> |
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<para> |
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This parameter specifies the time stamp up to which recovery |
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will proceed. |
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At most one of <varname>recovery_target_time</> and |
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<xref linkend="recovery-target-xid"> can be specified. |
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The default is to recover to the end of the WAL log. |
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The precise stopping point is also influenced by |
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<xref linkend="recovery-target-inclusive">. |
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</para> |
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</listitem> |
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</varlistentry> |
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|
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<varlistentry id="recovery-target-xid" xreflabel="recovery_target_xid"> |
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<term><varname>recovery_target_xid</varname> (<type>string</type>)</term> |
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<listitem> |
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<para> |
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This parameter specifies the transaction ID up to which recovery |
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will proceed. Keep in mind |
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that while transaction IDs are assigned sequentially at transaction |
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start, transactions can complete in a different numeric order. |
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The transactions that will be recovered are those that committed |
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before (and optionally including) the specified one. |
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At most one of <varname>recovery_target_xid</> and |
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<xref linkend="recovery-target-time"> can be specified. |
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The default is to recover to the end of the WAL log. |
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The precise stopping point is also influenced by |
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<xref linkend="recovery-target-inclusive">. |
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</para> |
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</listitem> |
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</varlistentry> |
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|
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<varlistentry id="recovery-target-inclusive" |
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xreflabel="recovery_target_inclusive"> |
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<term><varname>recovery_target_inclusive</varname> |
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(<type>boolean</type>) |
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</term> |
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<listitem> |
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<para> |
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Specifies whether we stop just after the specified recovery target |
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(<literal>true</literal>), or just before the recovery target |
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(<literal>false</literal>). |
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Applies to both <xref linkend="recovery-target-time"> |
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and <xref linkend="recovery-target-xid">, whichever one is |
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specified for this recovery. This indicates whether transactions |
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having exactly the target commit time or ID, respectively, will |
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be included in the recovery. Default is <literal>true</>. |
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</para> |
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</listitem> |
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</varlistentry> |
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|
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<varlistentry id="recovery-target-timeline" |
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xreflabel="recovery_target_timeline"> |
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<term><varname>recovery_target_timeline</varname> |
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(<type>string</type>) |
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</term> |
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<listitem> |
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<para> |
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Specifies recovering into a particular timeline. The default is |
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to recover along the same timeline that was current when the |
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base backup was taken. You only need to set this parameter |
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in complex re-recovery situations, where you need to return to |
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a state that itself was reached after a point-in-time recovery. |
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See <xref linkend="backup-timelines"> for discussion. |
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</para> |
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</listitem> |
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</varlistentry> |
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|
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</variablelist> |
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</sect1> |
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|
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<sect1 id="standby-settings"> |
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<title>Standby server settings</title> |
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<variablelist> |
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<varlistentry id="standby-mode" xreflabel="standby_mode"> |
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<term><varname>standby_mode</varname> (<type>boolean</type>)</term> |
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<listitem> |
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<para> |
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Specifies whether to start the <productname>PostgreSQL</> server as |
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a standby. If this parameter is <literal>on</>, the server will |
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not end recovery when the end of archived WAL is reached, but |
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will keep trying to continue recovery using <varname>restore_command</> |
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and by connecting to the primary server as specified by the |
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<varname>primary_conninfo</> setting. |
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</para> |
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</listitem> |
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</varlistentry> |
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<varlistentry id="primary-conninfo" xreflabel="primary_conninfo"> |
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<term><varname>primary_conninfo</varname> (<type>string</type>)</term> |
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<listitem> |
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<para> |
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Specifies a connection string to be used for the standby server |
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to connect with the primary. This string is in the same format as |
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described in <xref linkend="libpq-connect">. If any option is |
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unspecified in this string, then the corresponding environment |
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variable (see <xref linkend="libpq-envars">) is checked. If the |
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environment variable is not set either, then |
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defaults are used. |
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</para> |
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<para> |
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The built-in replication requires that a host name (or host address) |
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or port number which the primary server listens on be |
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specified in this string. Also ensure that a role with |
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the <literal>SUPERUSER</> and <literal>LOGIN</> privileges on the |
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primary is set (see |
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<xref linkend="streaming-replication-authentication">). Note that |
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the password needs to be set if the primary demands password |
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authentication. |
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</para> |
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<para> |
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This setting has no effect if <varname>standby_mode</> is <literal>off</>. |
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</para> |
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</listitem> |
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</varlistentry> |
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<varlistentry id="trigger-file" xreflabel="trigger_file"> |
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<term><varname>trigger_file</varname> (<type>string</type>)</term> |
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<listitem> |
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<para> |
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Specifies a trigger file whose presence ends recovery in the |
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standby. If no trigger file is specified, the standby never exits |
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recovery. |
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This setting has no effect if <varname>standby_mode</> is <literal>off</>. |
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</para> |
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</listitem> |
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</varlistentry> |
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|
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</variablelist> |
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</sect1> |
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</chapter> |
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