<para>

If more flexibility in copying the backup files is needed, a lower

level process can be used for standalone hot backups as well.

To prepare for low level standalone hot backups, set <varname>wal_level</> to

To prepare for low level standalone hot backups, make sure

<varname>wal_level</> is set to

<literal>replica</> or higher, <varname>archive_mode</> to

<literal>on</>, and set up an <varname>archive_command</> that performs

archiving only when a <emphasis>switch file</> exists. For example:

</term>

<listitem>

<para>

<varname>wal_level</> determines how much information is written

tothe WAL. The default value is <literal>minimal</>, which writes

only the information neededtorecover from a crash or immediate

shutdown. <literal>replica</>adds logging required for WAL

archiving as well asinformation required torun

read-only queries on a standby server. Finally,

<varname>wal_level</> determines how much information is written to

the WAL. The default value is <literal>replica</>, which writes enough

datatosupport WAL archiving and replication, including running

read-only queries on a standby server. <literal>minimal</>removes all

logging except theinformation required torecover from a crash or

immediate shutdown. Finally,

<literal>logical</> adds information necessary to support logical

decoding. Each level includes the information logged at all lower

levels. This parameter can only be set at server start.

Specifies the maximum number of concurrent connections from

standby servers or streaming base backup clients (i.e., the

maximum number of simultaneously running WAL sender

processes). The default iszero, meaning replication is

processes). The default is10. The value 0 means replication is

disabled. WAL sender processes count towards the total number

of connections, so the parameter cannot be set higher than

<xref linkend="guc-max-connections">. Abrupt streaming client

<para>

Specifies the maximum number of replication slots

(see <xref linkend="streaming-replication-slots">) that the server

can support. The default iszero. This parameter can only be set at

can support. The default is10. This parameter can only be set at

server start.

<varname>wal_level</varname> must be set

to <literal>replica</literal> or higher to allow replication slots to

},

&max_wal_senders,

0,0,MAX_BACKENDS,

10,0,MAX_BACKENDS,

NULL,NULL,NULL

},

},

&max_replication_slots,

0,0,MAX_BACKENDS/* XXX? */ ,

10,0,MAX_BACKENDS/* XXX? */ ,

NULL,NULL,NULL

},

},

&wal_level,

WAL_LEVEL_MINIMAL,wal_level_options,

WAL_LEVEL_REPLICA,wal_level_options,

NULL,NULL,NULL

},

# - Settings -

#wal_level =minimal# minimal, replica, or logical

#wal_level =replica# minimal, replica, or logical

# (change requires restart)

#fsync = on# flush data to disk for crash safety

# (turning this off can cause

# Set these on the master and on any standby that will send replication data.

#max_wal_senders =0# max number of walsender processes

#max_wal_senders =10# max number of walsender processes

# (change requires restart)

#wal_keep_segments = 0# in logfile segments, 16MB each; 0 disables

#wal_sender_timeout = 60s# in milliseconds; 0 disables

#max_replication_slots =0# max number of replication slots

#max_replication_slots =10# max number of replication slots

# (change requires restart)

#track_commit_timestamp = off# collect timestamp of transaction commit

# (change requires restart)

'postgresql.conf',qq{

});

$master->start;

$master->backup($bkplabel);

'postgresql.conf',qq{

});

$master->start;

$master->backup($bkplabel);

if ($params{allows_streaming})

{

print$conf"wal_level = replica\n";

print$conf"max_wal_senders = 5\n";

print$conf"wal_keep_segments = 20\n";

print$conf"max_wal_size = 128MB\n";

print$conf"hot_standby = on\n";

print$conf"max_connections = 10\n";

}

{

print$conf"wal_level = minimal\n";

print$conf"max_wal_senders = 0\n";

}

if ($TestLib::windows_os)

{

$node_master->init(allows_streaming=> 1);

$node_master->append_conf(

'postgresql.conf',qq(

));

$node_master->start;

$node_master->append_conf('postgresql.conf',qq{