<programlisting>

SELECT * FROM pg_stop_backup(false);

</programlisting>

This terminates the backup mode and performs an automatic switch to

the next WAL segment. The reason for the switch is to arrange for

This terminates backup mode. On a primary, it also performs an automatic

switch to the next WAL segment. On a standby, it is not possible to

automatically switch WAL segments, so you may wish to run

<function>pg_switch_xlog</function> on the primary to perform a manual

switch. The reason for the switch is to arrange for

the last WAL segment file written during the backup interval to be

ready to archive.

</para>

Once the WAL segment files active during the backup are archived, you are

done. The file identified by <function>pg_stop_backup</>'s first return

value is the last segment that is required to form a complete set of

backup files.If <varname>archive_mode</> is enabled,

backup files.On a primary, if <varname>archive_mode</> is enabled,

<function>pg_stop_backup</> does not return until the last segment has

been archived.

Archiving of these files happens automatically since you have

<function>pg_stop_backup</> terminates because of this your backup

may not be valid.

</para>

<para>

Note that on a standby <function>pg_stop_backup</> does not wait for

WAL segments to be archived so the backup process must ensure that all WAL

segments required for the backup are successfully archived.

</para>

</listitem>

</orderedlist>

</para>

<title>Making an exclusive low level backup</title>

<para>

The process for an exclusive backup is mostly the same as for a

non-exclusive one, but it differs in a few key steps.It does not allow

more than one concurrent backup to run, andthere can be some issues on

the server if it crashes during the backup.Prior to PostgreSQL 9.6, this

non-exclusive one, but it differs in a few key steps.This type of backup

can only be taken on a primary anddoes not allow concurrent backups.

Prior to<productname>PostgreSQL</> 9.6, this

was the only low-level method available, but it is now recommended that

all users upgrade their scripts to use non-exclusive backups if possible.

</para>

<xref linkend="backup-lowlevel-base-backup-data"> for things to

consider during this backup.

</para>

<para>

Note that if the server crashes during the backup it may not be

possible to restart until the <literal>backup_label</> file has been

manually deleted from the <envar>PGDATA</envar> directory.

</para>

</listitem>

<listitem>

<para>

<function>pg_start_backup</>. In a non-exclusive backup, the contents of

the <filename>backup_label</> and <filename>tablespace_map</> are returned

in the result of the function, and should be written to files in the

backup (and not in the data directory).

backup (and not in the data directory). When executed on a primary

<function>pg_stop_backup</> will wait for WAL to be archived, provided that

archiving is enabled.

</para>

<para>

The function also creates a backup history file in the transaction log

On a standby <function>pg_stop_backup</> will return immediately without

waiting, so it's important to verify that all required WAL segments have

been archived. If write activity on the primary is low, it may be useful

to run <function>pg_switch_xlog</> on the primary in order to trigger a

segment switch.

</para>

<para>

When executed on a primary, the function also creates a backup history file

in the write-ahead log

archive area. The history file includes the label given to

<function>pg_start_backup</>, the starting and ending transaction log locations for

the backup, and the starting and ending times of the backup. The return