pgsql: Integrate recovery.conf into postgresql.conf

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index db1a2d4..d95d0a7 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -3221,7 +3221,7 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"'  # Windows
       <varname>recovery_target_lsn</varname>, <varname>recovery_target_name</varname>,
       <varname>recovery_target_time</varname>, or <varname>recovery_target_xid</varname>
       can be used; if more than one of these is specified in the configuration
-      file, the last entry will be used.
+      file, a fatal error will be raised.
       These parameters can only be set at server start.
      </para>
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index c80b14e..01fbab8 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -261,11 +261,18 @@ static bool restoredFromArchive = false;
 static char *replay_image_masked = NULL;
 static char *master_image_masked = NULL;
 
+/* recovery_target* original GUC values */
+char *recovery_target_string;
+char *recovery_target_xid_string;
+char *recovery_target_time_string;
+char *recovery_target_name_string;
+char *recovery_target_lsn_string;
+
 /* options formerly taken from recovery.conf for archive recovery */
 char	   *recoveryRestoreCommand = NULL;
 char	   *recoveryEndCommand = NULL;
 char	   *archiveCleanupCommand = NULL;
-RecoveryTargetType recoveryTarget = RECOVERY_TARGET_UNSET;
+static RecoveryTargetType recoveryTarget = RECOVERY_TARGET_UNSET;
 bool		recoveryTargetInclusive = true;
 int			recoveryTargetAction = RECOVERY_TARGET_ACTION_PAUSE;
 TransactionId recoveryTargetXid;
@@ -5381,9 +5388,42 @@ readRecoverySignalFile(void)
 static void
 validateRecoveryParameters(void)
 {
+	uint8 targetSettingsCount = 0;
+
 	if (!ArchiveRecoveryRequested)
 		return;
 
+	/* Check for mutually exclusive target actions */
+	if (strcmp(recovery_target_string, "") != 0)
+	{
+		++targetSettingsCount;
+		recoveryTarget = RECOVERY_TARGET_IMMEDIATE;
+	}
+	if (strcmp(recovery_target_name_string, "") != 0)
+	{
+		++targetSettingsCount;
+		recoveryTarget = RECOVERY_TARGET_NAME;
+	}
+	if (strcmp(recovery_target_lsn_string, "") != 0)
+	{
+		++targetSettingsCount;
+		recoveryTarget = RECOVERY_TARGET_LSN;
+	}
+	if (strcmp(recovery_target_xid_string, "") != 0)
+	{
+		++targetSettingsCount;
+		recoveryTarget = RECOVERY_TARGET_XID;
+	}
+	if (strcmp(recovery_target_time_string, "") != 0)
+	{
+		++targetSettingsCount;
+		recoveryTarget = RECOVERY_TARGET_TIME;
+	}
+	if (targetSettingsCount > 1)
+		ereport(FATAL,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("can not specify multiple recovery targets")));
+
 	/*
 	 * Check for compulsory parameters
 	 */
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 6497393..fd85484 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -199,7 +199,6 @@ static const char *show_data_directory_mode(void);
 static bool check_recovery_target_timeline(char **newval, void **extra, GucSource source);
 static void assign_recovery_target_timeline(const char *newval, void *extra);
 static bool check_recovery_target(char **newval, void **extra, GucSource source);
-static void assign_recovery_target(const char *newval, void *extra);
 static bool check_recovery_target_xid(char **newval, void **extra, GucSource source);
 static void assign_recovery_target_xid(const char *newval, void *extra);
 static bool check_recovery_target_time(char **newval, void **extra, GucSource source);
@@ -549,12 +548,6 @@ static bool data_checksums;
 static bool integer_datetimes;
 static bool assert_enabled;
 static char *recovery_target_timeline_string;
-static char *recovery_target_string;
-static char *recovery_target_xid_string;
-static char *recovery_target_time_string;
-static char *recovery_target_name_string;
-static char *recovery_target_lsn_string;
-
 
 /* should be static, but commands/variable.c needs to get at this */
 char	   *role_string;
@@ -3385,7 +3378,7 @@ static struct config_string ConfigureNamesString[] =
 		},
 		&recovery_target_string,
 		"",
-		check_recovery_target, assign_recovery_target, NULL
+		check_recovery_target, NULL, NULL
 	},
 	{
 		{"recovery_target_xid", PGC_POSTMASTER, WAL_RECOVERY_TARGET,
@@ -11062,18 +11055,6 @@ check_recovery_target(char **newval, void **extra, GucSource source)
 	return true;
 }
 
-static void
-assign_recovery_target(const char *newval, void *extra)
-{
-	if (newval && strcmp(newval, "") != 0)
-		recoveryTarget = RECOVERY_TARGET_IMMEDIATE;
-	else
-		/*
-		 * Reset recoveryTarget to RECOVERY_TARGET_UNSET to proper handle user
-		 * setting multiple recovery_target with blank value on last.
-		 */
-		recoveryTarget = RECOVERY_TARGET_UNSET;
-}
 
 static bool
 check_recovery_target_xid(char **newval, void **extra, GucSource source)
@@ -11100,11 +11081,8 @@ assign_recovery_target_xid(const char *newval, void *extra)
 {
 	if (newval && strcmp(newval, "") != 0)
 	{
-		recoveryTarget = RECOVERY_TARGET_XID;
 		recoveryTargetXid = *((TransactionId *) extra);
 	}
-	else
-		recoveryTarget = RECOVERY_TARGET_UNSET;
 }
 
 static bool
@@ -11163,11 +11141,8 @@ assign_recovery_target_time(const char *newval, void *extra)
 {
 	if (newval && strcmp(newval, "") != 0)
 	{
-		recoveryTarget = RECOVERY_TARGET_TIME;
 		recoveryTargetTime = *((TimestampTz *) extra);
 	}
-	else
-		recoveryTarget = RECOVERY_TARGET_UNSET;
 }
 
 static bool
@@ -11188,11 +11163,8 @@ assign_recovery_target_name(const char *newval, void *extra)
 {
 	if (newval && strcmp(newval, "") != 0)
 	{
-		recoveryTarget = RECOVERY_TARGET_NAME;
 		recoveryTargetName = (char *) newval;
 	}
-	else
-		recoveryTarget = RECOVERY_TARGET_UNSET;
 }
 
 static bool
@@ -11242,11 +11214,8 @@ assign_recovery_target_lsn(const char *newval, void *extra)
 {
 	if (newval && strcmp(newval, "") != 0)
 	{
-		recoveryTarget = RECOVERY_TARGET_LSN;
 		recoveryTargetLSN = *((XLogRecPtr *) extra);
 	}
-	else
-		recoveryTarget = RECOVERY_TARGET_UNSET;
 }
 
 static bool
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index f3a7ba4..0addbb7 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -127,13 +127,17 @@ extern int	recoveryTargetAction;
 extern int	recovery_min_apply_delay;
 extern char *PrimaryConnInfo;
 extern char *PrimarySlotName;
+extern char *recovery_target_string;
+extern char *recovery_target_xid_string;
+extern char *recovery_target_time_string;
+extern char *recovery_target_name_string;
+extern char *recovery_target_lsn_string;
 
 /* indirectly set via GUC system */
 extern TransactionId recoveryTargetXid;
 extern TimestampTz recoveryTargetTime;
 extern char *recoveryTargetName;
 extern XLogRecPtr recoveryTargetLSN;
-extern RecoveryTargetType recoveryTarget;
 extern char *PromoteTriggerFile;
 extern RecoveryTargetTimeLineGoal recoveryTargetTimeLineGoal;
 extern TimeLineID recoveryTargetTLIRequested;
diff --git a/src/test/recovery/t/003_recovery_targets.pl b/src/test/recovery/t/003_recovery_targets.pl
index f6f2e8b..1a90ad9 100644
--- a/src/test/recovery/t/003_recovery_targets.pl
+++ b/src/test/recovery/t/003_recovery_targets.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 9;
+use Test::More tests => 5;
 
 # Create and test a standby from given backup, with a certain recovery target.
 # Choose $until_lsn later than the transaction commit that causes the row
@@ -114,32 +114,3 @@ test_recovery_standby('name', 'standby_4', $node_master, \@recovery_params,
 @recovery_params = ("recovery_target_lsn = '$recovery_lsn'");
 test_recovery_standby('LSN', 'standby_5', $node_master, \@recovery_params,
 	"5000", $lsn5);
-
-# Multiple targets
-# Last entry has priority (note that an array respects the order of items
-# not hashes).
-@recovery_params = (
-	"recovery_target_name = '$recovery_name'",
-	"recovery_target_xid  = '$recovery_txid'",
-	"recovery_target_time = '$recovery_time'");
-test_recovery_standby('name + XID + time',
-	'standby_6', $node_master, \@recovery_params, "3000", $lsn3);
-@recovery_params = (
-	"recovery_target_time = '$recovery_time'",
-	"recovery_target_name = '$recovery_name'",
-	"recovery_target_xid  = '$recovery_txid'");
-test_recovery_standby('time + name + XID',
-	'standby_7', $node_master, \@recovery_params, "2000", $lsn2);
-@recovery_params = (
-	"recovery_target_xid  = '$recovery_txid'",
-	"recovery_target_time = '$recovery_time'",
-	"recovery_target_name = '$recovery_name'");
-test_recovery_standby('XID + time + name',
-	'standby_8', $node_master, \@recovery_params, "4000", $lsn4);
-@recovery_params = (
-	"recovery_target_xid  = '$recovery_txid'",
-	"recovery_target_time = '$recovery_time'",
-	"recovery_target_name = '$recovery_name'",
-	"recovery_target_lsn = '$recovery_lsn'",);
-test_recovery_standby('XID + time + name + LSN',
-	'standby_9', $node_master, \@recovery_params, "5000", $lsn5);

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index db1a2d4..49caa0c 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -3217,19 +3217,19 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"'  # Windows
      <para>
       By default, recovery will recover to the end of the WAL log. The
       following parameters can be used to specify an earlier stopping point.
-      At most one of <varname>recovery_target</varname>,
+      At most one of <varname>recovery_target_immediate</varname>,
       <varname>recovery_target_lsn</varname>, <varname>recovery_target_name</varname>,
       <varname>recovery_target_time</varname>, or <varname>recovery_target_xid</varname>
       can be used; if more than one of these is specified in the configuration
-      file, the last entry will be used.
+      file, a fatal error will be raised.
       These parameters can only be set at server start.
      </para>
 
      <variablelist>
-     <varlistentry id="guc-recovery-target" xreflabel="recovery_target">
-      <term><varname>recovery_target</varname><literal> = 'immediate'</literal>
+     <varlistentry id="guc-recovery-target-immediate" xreflabel="recovery_target_immediate">
+      <term><varname>recovery_target_immediate</varname> (<type>boolean</type>)
       <indexterm>
-        <primary><varname>recovery_target</varname> configuration parameter</primary>
+        <primary><varname>recovery_target_immediate</varname> configuration parameter</primary>
       </indexterm>
       </term>
       <listitem>
@@ -3239,10 +3239,6 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"'  # Windows
         from an online backup, this means the point where taking the backup
         ended.
        </para>
-       <para>
-        Technically, this is a string parameter, but <literal>'immediate'</literal>
-        is currently the only allowed value.
-       </para>
       </listitem>
      </varlistentry>
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index c80b14e..cd29606 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -261,13 +261,21 @@ static bool restoredFromArchive = false;
 static char *replay_image_masked = NULL;
 static char *master_image_masked = NULL;
 
+/* recovery_target* original GUC values */
+char *recovery_target_string;
+char *recovery_target_xid_string;
+char *recovery_target_time_string;
+char *recovery_target_name_string;
+char *recovery_target_lsn_string;
+
 /* options formerly taken from recovery.conf for archive recovery */
 char	   *recoveryRestoreCommand = NULL;
 char	   *recoveryEndCommand = NULL;
 char	   *archiveCleanupCommand = NULL;
-RecoveryTargetType recoveryTarget = RECOVERY_TARGET_UNSET;
+static RecoveryTargetType recoveryTarget = RECOVERY_TARGET_UNSET;
 bool		recoveryTargetInclusive = true;
 int			recoveryTargetAction = RECOVERY_TARGET_ACTION_PAUSE;
+bool 		recoveryTargetImmediate;
 TransactionId recoveryTargetXid;
 TimestampTz recoveryTargetTime;
 char	   *recoveryTargetName;
@@ -5381,9 +5389,42 @@ readRecoverySignalFile(void)
 static void
 validateRecoveryParameters(void)
 {
+	uint8 targetSettingsCount = 0;
+
 	if (!ArchiveRecoveryRequested)
 		return;
 
+	/* Check for mutually exclusive target actions */
+	if (recoveryTargetImmediate)
+	{
+		++targetSettingsCount;
+		recoveryTarget = RECOVERY_TARGET_IMMEDIATE;
+	}
+	if (strcmp(recovery_target_name_string, "") != 0)
+	{
+		++targetSettingsCount;
+		recoveryTarget = RECOVERY_TARGET_NAME;
+	}
+	if (strcmp(recovery_target_lsn_string, "") != 0)
+	{
+		++targetSettingsCount;
+		recoveryTarget = RECOVERY_TARGET_LSN;
+	}
+	if (strcmp(recovery_target_xid_string, "") != 0)
+	{
+		++targetSettingsCount;
+		recoveryTarget = RECOVERY_TARGET_XID;
+	}
+	if (strcmp(recovery_target_time_string, "") != 0)
+	{
+		++targetSettingsCount;
+		recoveryTarget = RECOVERY_TARGET_TIME;
+	}
+	if (targetSettingsCount > 1)
+		ereport(FATAL,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("can not specify multiple recovery targets")));
+
 	/*
 	 * Check for compulsory parameters
 	 */
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 6497393..9d6879c 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -198,8 +198,6 @@ static const char *show_log_file_mode(void);
 static const char *show_data_directory_mode(void);
 static bool check_recovery_target_timeline(char **newval, void **extra, GucSource source);
 static void assign_recovery_target_timeline(const char *newval, void *extra);
-static bool check_recovery_target(char **newval, void **extra, GucSource source);
-static void assign_recovery_target(const char *newval, void *extra);
 static bool check_recovery_target_xid(char **newval, void **extra, GucSource source);
 static void assign_recovery_target_xid(const char *newval, void *extra);
 static bool check_recovery_target_time(char **newval, void **extra, GucSource source);
@@ -549,12 +547,6 @@ static bool data_checksums;
 static bool integer_datetimes;
 static bool assert_enabled;
 static char *recovery_target_timeline_string;
-static char *recovery_target_string;
-static char *recovery_target_xid_string;
-static char *recovery_target_time_string;
-static char *recovery_target_name_string;
-static char *recovery_target_lsn_string;
-
 
 /* should be static, but commands/variable.c needs to get at this */
 char	   *role_string;
@@ -1674,6 +1666,16 @@ static struct config_bool ConfigureNamesBool[] =
 	},
 
 	{
+		{"recovery_target_immediate", PGC_POSTMASTER, WAL_RECOVERY_TARGET,
+			gettext_noop("End recovery as soon as a consistent state is reached."),
+			NULL
+		},
+		&recoveryTargetImmediate,
+		false,
+		NULL, NULL, NULL
+	},
+
+	{
 		{"hot_standby", PGC_POSTMASTER, REPLICATION_STANDBY,
 			gettext_noop("Allows connections and queries during recovery."),
 			NULL
@@ -3379,15 +3381,6 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"recovery_target", PGC_POSTMASTER, WAL_RECOVERY_TARGET,
-			gettext_noop("Set to 'immediate' to end recovery as soon as a consistent state is reached."),
-			NULL
-		},
-		&recovery_target_string,
-		"",
-		check_recovery_target, assign_recovery_target, NULL
-	},
-	{
 		{"recovery_target_xid", PGC_POSTMASTER, WAL_RECOVERY_TARGET,
 			gettext_noop("Sets the transaction ID up to which recovery will proceed."),
 			NULL
@@ -11052,30 +11045,6 @@ assign_recovery_target_timeline(const char *newval, void *extra)
 }
 
 static bool
-check_recovery_target(char **newval, void **extra, GucSource source)
-{
-	if (strcmp(*newval, "immediate") != 0 && strcmp(*newval, "") != 0)
-	{
-		GUC_check_errdetail("The only allowed value is \"immediate\".");
-		return false;
-	}
-	return true;
-}
-
-static void
-assign_recovery_target(const char *newval, void *extra)
-{
-	if (newval && strcmp(newval, "") != 0)
-		recoveryTarget = RECOVERY_TARGET_IMMEDIATE;
-	else
-		/*
-		 * Reset recoveryTarget to RECOVERY_TARGET_UNSET to proper handle user
-		 * setting multiple recovery_target with blank value on last.
-		 */
-		recoveryTarget = RECOVERY_TARGET_UNSET;
-}
-
-static bool
 check_recovery_target_xid(char **newval, void **extra, GucSource source)
 {
 	if (strcmp(*newval, "") != 0)
@@ -11100,11 +11069,8 @@ assign_recovery_target_xid(const char *newval, void *extra)
 {
 	if (newval && strcmp(newval, "") != 0)
 	{
-		recoveryTarget = RECOVERY_TARGET_XID;
 		recoveryTargetXid = *((TransactionId *) extra);
 	}
-	else
-		recoveryTarget = RECOVERY_TARGET_UNSET;
 }
 
 static bool
@@ -11163,11 +11129,8 @@ assign_recovery_target_time(const char *newval, void *extra)
 {
 	if (newval && strcmp(newval, "") != 0)
 	{
-		recoveryTarget = RECOVERY_TARGET_TIME;
 		recoveryTargetTime = *((TimestampTz *) extra);
 	}
-	else
-		recoveryTarget = RECOVERY_TARGET_UNSET;
 }
 
 static bool
@@ -11188,11 +11151,8 @@ assign_recovery_target_name(const char *newval, void *extra)
 {
 	if (newval && strcmp(newval, "") != 0)
 	{
-		recoveryTarget = RECOVERY_TARGET_NAME;
 		recoveryTargetName = (char *) newval;
 	}
-	else
-		recoveryTarget = RECOVERY_TARGET_UNSET;
 }
 
 static bool
@@ -11242,11 +11202,8 @@ assign_recovery_target_lsn(const char *newval, void *extra)
 {
 	if (newval && strcmp(newval, "") != 0)
 	{
-		recoveryTarget = RECOVERY_TARGET_LSN;
 		recoveryTargetLSN = *((XLogRecPtr *) extra);
 	}
-	else
-		recoveryTarget = RECOVERY_TARGET_UNSET;
 }
 
 static bool
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index ee9ec6a..ccdc94d 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -246,8 +246,8 @@
 
 # Set these only when performing a targeted recovery.
 
-#recovery_target = ''		# 'immediate' to end recovery as soon as a
-                                # consistent state is reached
+#recovery_target_immediate = false	# end recovery as soon as a
+									# consistent state is reached
 				# (change requires restart)
 #recovery_target_name = ''	# the named restore point to which recovery will proceed
 				# (change requires restart)
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index f3a7ba4..d257f4f 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -127,13 +127,17 @@ extern int	recoveryTargetAction;
 extern int	recovery_min_apply_delay;
 extern char *PrimaryConnInfo;
 extern char *PrimarySlotName;
+extern bool recoveryTargetImmediate;
+extern char *recovery_target_xid_string;
+extern char *recovery_target_time_string;
+extern char *recovery_target_name_string;
+extern char *recovery_target_lsn_string;
 
 /* indirectly set via GUC system */
 extern TransactionId recoveryTargetXid;
 extern TimestampTz recoveryTargetTime;
 extern char *recoveryTargetName;
 extern XLogRecPtr recoveryTargetLSN;
-extern RecoveryTargetType recoveryTarget;
 extern char *PromoteTriggerFile;
 extern RecoveryTargetTimeLineGoal recoveryTargetTimeLineGoal;
 extern TimeLineID recoveryTargetTLIRequested;
diff --git a/src/test/recovery/t/003_recovery_targets.pl b/src/test/recovery/t/003_recovery_targets.pl
index f6f2e8b..df261f0 100644
--- a/src/test/recovery/t/003_recovery_targets.pl
+++ b/src/test/recovery/t/003_recovery_targets.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 9;
+use Test::More tests => 6;
 
 # Create and test a standby from given backup, with a certain recovery target.
 # Choose $until_lsn later than the transaction commit that causes the row
@@ -53,7 +53,7 @@ $node_master->init(has_archiving => 1, allows_streaming => 1);
 $node_master->start;
 
 # Create data before taking the backup, aimed at testing
-# recovery_target = 'immediate'
+# recovery_target_immediate
 $node_master->safe_psql('postgres',
 	"CREATE TABLE tab_int AS SELECT generate_series(1,1000) AS a");
 my $lsn1 =
@@ -99,7 +99,7 @@ $node_master->safe_psql('postgres',
 $node_master->safe_psql('postgres', "SELECT pg_switch_wal()");
 
 # Test recovery targets
-my @recovery_params = ("recovery_target = 'immediate'");
+my @recovery_params = ("recovery_target_immediate = true");
 test_recovery_standby('immediate target',
 	'standby_1', $node_master, \@recovery_params, "1000", $lsn1);
 @recovery_params = ("recovery_target_xid = '$recovery_txid'");
@@ -115,31 +115,11 @@ test_recovery_standby('name', 'standby_4', $node_master, \@recovery_params,
 test_recovery_standby('LSN', 'standby_5', $node_master, \@recovery_params,
 	"5000", $lsn5);
 
-# Multiple targets
-# Last entry has priority (note that an array respects the order of items
-# not hashes).
-@recovery_params = (
-	"recovery_target_name = '$recovery_name'",
-	"recovery_target_xid  = '$recovery_txid'",
-	"recovery_target_time = '$recovery_time'");
-test_recovery_standby('name + XID + time',
-	'standby_6', $node_master, \@recovery_params, "3000", $lsn3);
-@recovery_params = (
-	"recovery_target_time = '$recovery_time'",
-	"recovery_target_name = '$recovery_name'",
-	"recovery_target_xid  = '$recovery_txid'");
-test_recovery_standby('time + name + XID',
-	'standby_7', $node_master, \@recovery_params, "2000", $lsn2);
-@recovery_params = (
-	"recovery_target_xid  = '$recovery_txid'",
-	"recovery_target_time = '$recovery_time'",
-	"recovery_target_name = '$recovery_name'");
-test_recovery_standby('XID + time + name',
-	'standby_8', $node_master, \@recovery_params, "4000", $lsn4);
-@recovery_params = (
-	"recovery_target_xid  = '$recovery_txid'",
-	"recovery_target_time = '$recovery_time'",
-	"recovery_target_name = '$recovery_name'",
-	"recovery_target_lsn = '$recovery_lsn'",);
-test_recovery_standby('XID + time + name + LSN',
-	'standby_9', $node_master, \@recovery_params, "5000", $lsn5);
+# multiple recovery targets are disallowed
+my $node_standby6 = get_new_node('standby_6');
+$node_standby6->init_from_backup($node_master, 'my_backup',
+	has_restoring => 1);
+$node_standby6->append_conf('postgresql.conf', "recovery_target_lsn = '$recovery_lsn'");
+$node_standby6->append_conf('postgresql.conf', "recovery_target_xid = '$recovery_txid'");
+$node_standby6->command_fails(['pg_ctl', '-D', $node_standby6->data_dir, '-l',
+	$node_standby6->logfile, 'start']);

From d5cb3f3a30bd045283c9848bd39ff012c817d908 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter_e@gmx.net>
Date: Tue, 27 Nov 2018 13:43:54 +0100
Subject: [PATCH] WIP Only allow one recovery target setting

---
 src/backend/utils/misc/guc.c | 29 +++++++++++++++--------------
 src/include/access/xlog.h    |  2 +-
 2 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 6497393c03..dd2caee95b 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -11065,14 +11065,11 @@ check_recovery_target(char **newval, void **extra, GucSource source)
 static void
 assign_recovery_target(const char *newval, void *extra)
 {
+	if (recoveryTarget)
+		elog(ERROR, "multiple recovery targets specified");
+
 	if (newval && strcmp(newval, "") != 0)
 		recoveryTarget = RECOVERY_TARGET_IMMEDIATE;
-	else
-		/*
-		 * Reset recoveryTarget to RECOVERY_TARGET_UNSET to proper handle user
-		 * setting multiple recovery_target with blank value on last.
-		 */
-		recoveryTarget = RECOVERY_TARGET_UNSET;
 }
 
 static bool
@@ -11098,13 +11095,14 @@ check_recovery_target_xid(char **newval, void **extra, GucSource source)
 static void
 assign_recovery_target_xid(const char *newval, void *extra)
 {
+	if (recoveryTarget)
+		elog(ERROR, "multiple recovery targets specified");
+
 	if (newval && strcmp(newval, "") != 0)
 	{
 		recoveryTarget = RECOVERY_TARGET_XID;
 		recoveryTargetXid = *((TransactionId *) extra);
 	}
-	else
-		recoveryTarget = RECOVERY_TARGET_UNSET;
 }
 
 static bool
@@ -11161,13 +11159,14 @@ check_recovery_target_time(char **newval, void **extra, GucSource source)
 static void
 assign_recovery_target_time(const char *newval, void *extra)
 {
+	if (recoveryTarget)
+		elog(ERROR, "multiple recovery targets specified");
+
 	if (newval && strcmp(newval, "") != 0)
 	{
 		recoveryTarget = RECOVERY_TARGET_TIME;
 		recoveryTargetTime = *((TimestampTz *) extra);
 	}
-	else
-		recoveryTarget = RECOVERY_TARGET_UNSET;
 }
 
 static bool
@@ -11186,13 +11185,14 @@ check_recovery_target_name(char **newval, void **extra, GucSource source)
 static void
 assign_recovery_target_name(const char *newval, void *extra)
 {
+	if (recoveryTarget)
+		elog(ERROR, "multiple recovery targets specified");
+
 	if (newval && strcmp(newval, "") != 0)
 	{
 		recoveryTarget = RECOVERY_TARGET_NAME;
 		recoveryTargetName = (char *) newval;
 	}
-	else
-		recoveryTarget = RECOVERY_TARGET_UNSET;
 }
 
 static bool
@@ -11240,13 +11240,14 @@ check_recovery_target_lsn(char **newval, void **extra, GucSource source)
 static void
 assign_recovery_target_lsn(const char *newval, void *extra)
 {
+	if (recoveryTarget)
+		elog(ERROR, "multiple recovery targets specified");
+
 	if (newval && strcmp(newval, "") != 0)
 	{
 		recoveryTarget = RECOVERY_TARGET_LSN;
 		recoveryTargetLSN = *((XLogRecPtr *) extra);
 	}
-	else
-		recoveryTarget = RECOVERY_TARGET_UNSET;
 }
 
 static bool
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index f3a7ba4d42..1fd4aec3c7 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -79,7 +79,7 @@ extern HotStandbyState standbyState;
  */
 typedef enum
 {
-	RECOVERY_TARGET_UNSET,
+	RECOVERY_TARGET_UNSET = 0,
 	RECOVERY_TARGET_XID,
 	RECOVERY_TARGET_TIME,
 	RECOVERY_TARGET_NAME,
-- 
2.19.1

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index db1a2d4..7cbea6e 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -3221,7 +3221,7 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"'  # Windows
       <varname>recovery_target_lsn</varname>, <varname>recovery_target_name</varname>,
       <varname>recovery_target_time</varname>, or <varname>recovery_target_xid</varname>
       can be used; if more than one of these is specified in the configuration
-      file, the last entry will be used.
+      file, a error will be raised.
       These parameters can only be set at server start.
      </para>
 
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 6497393..290a157 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -11065,14 +11065,11 @@ check_recovery_target(char **newval, void **extra, GucSource source)
 static void
 assign_recovery_target(const char *newval, void *extra)
 {
+	if (recoveryTarget)
+		elog(ERROR, "can not specify multiple recovery targets");
+
 	if (newval && strcmp(newval, "") != 0)
 		recoveryTarget = RECOVERY_TARGET_IMMEDIATE;
-	else
-		/*
-		 * Reset recoveryTarget to RECOVERY_TARGET_UNSET to proper handle user
-		 * setting multiple recovery_target with blank value on last.
-		 */
-		recoveryTarget = RECOVERY_TARGET_UNSET;
 }
 
 static bool
@@ -11098,13 +11095,14 @@ check_recovery_target_xid(char **newval, void **extra, GucSource source)
 static void
 assign_recovery_target_xid(const char *newval, void *extra)
 {
+	if (recoveryTarget)
+		elog(ERROR, "can not specify multiple recovery targets");
+
 	if (newval && strcmp(newval, "") != 0)
 	{
 		recoveryTarget = RECOVERY_TARGET_XID;
 		recoveryTargetXid = *((TransactionId *) extra);
 	}
-	else
-		recoveryTarget = RECOVERY_TARGET_UNSET;
 }
 
 static bool
@@ -11161,13 +11159,14 @@ check_recovery_target_time(char **newval, void **extra, GucSource source)
 static void
 assign_recovery_target_time(const char *newval, void *extra)
 {
+	if (recoveryTarget)
+		elog(ERROR, "can not specify multiple recovery targets");
+
 	if (newval && strcmp(newval, "") != 0)
 	{
 		recoveryTarget = RECOVERY_TARGET_TIME;
 		recoveryTargetTime = *((TimestampTz *) extra);
 	}
-	else
-		recoveryTarget = RECOVERY_TARGET_UNSET;
 }
 
 static bool
@@ -11186,13 +11185,14 @@ check_recovery_target_name(char **newval, void **extra, GucSource source)
 static void
 assign_recovery_target_name(const char *newval, void *extra)
 {
+	if (recoveryTarget)
+		elog(ERROR, "can not specify multiple recovery targets");
+
 	if (newval && strcmp(newval, "") != 0)
 	{
 		recoveryTarget = RECOVERY_TARGET_NAME;
 		recoveryTargetName = (char *) newval;
 	}
-	else
-		recoveryTarget = RECOVERY_TARGET_UNSET;
 }
 
 static bool
@@ -11240,13 +11240,14 @@ check_recovery_target_lsn(char **newval, void **extra, GucSource source)
 static void
 assign_recovery_target_lsn(const char *newval, void *extra)
 {
+	if (recoveryTarget)
+		elog(ERROR, "can not specify multiple recovery targets");
+
 	if (newval && strcmp(newval, "") != 0)
 	{
 		recoveryTarget = RECOVERY_TARGET_LSN;
 		recoveryTargetLSN = *((XLogRecPtr *) extra);
 	}
-	else
-		recoveryTarget = RECOVERY_TARGET_UNSET;
 }
 
 static bool
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index f3a7ba4..1fd4aec 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -79,7 +79,7 @@ extern HotStandbyState standbyState;
  */
 typedef enum
 {
-	RECOVERY_TARGET_UNSET,
+	RECOVERY_TARGET_UNSET = 0,
 	RECOVERY_TARGET_XID,
 	RECOVERY_TARGET_TIME,
 	RECOVERY_TARGET_NAME,
diff --git a/src/test/recovery/t/003_recovery_targets.pl b/src/test/recovery/t/003_recovery_targets.pl
index f6f2e8b..cba367c 100644
--- a/src/test/recovery/t/003_recovery_targets.pl
+++ b/src/test/recovery/t/003_recovery_targets.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 9;
+use Test::More tests => 10;
 
 # Create and test a standby from given backup, with a certain recovery target.
 # Choose $until_lsn later than the transaction commit that causes the row
@@ -115,31 +115,44 @@ test_recovery_standby('name', 'standby_4', $node_master, \@recovery_params,
 test_recovery_standby('LSN', 'standby_5', $node_master, \@recovery_params,
 	"5000", $lsn5);
 
-# Multiple targets
-# Last entry has priority (note that an array respects the order of items
-# not hashes).
+# multiple recovery targets are disallowed
+sub test_recovery_multiple_targets
+{
+	my $test_name       = shift;
+	my $node_name       = shift;
+	my $node_master     = shift;
+	my $recovery_params = shift;
+
+	my $node_standby = get_new_node($node_name);
+	$node_standby->init_from_backup($node_master, 'my_backup',
+		has_restoring => 1);
+
+	foreach my $param_item (@$recovery_params)
+	{
+		$node_standby->append_conf('postgresql.conf', qq($param_item));
+	}
+
+	$node_standby->command_fails(['pg_ctl', '-D', $node_standby->data_dir, '-l',
+		$node_standby->logfile, 'start'], "check standby content for $test_name");
+}
+
+@recovery_params = (
+	"recovery_target = 'immediate'",
+    "recovery_target_xid  = '$recovery_txid'",);
+test_recovery_multiple_targets('multi XID', 'standby_6', $node_master, \@recovery_params);
 @recovery_params = (
-	"recovery_target_name = '$recovery_name'",
-	"recovery_target_xid  = '$recovery_txid'",
-	"recovery_target_time = '$recovery_time'");
-test_recovery_standby('name + XID + time',
-	'standby_6', $node_master, \@recovery_params, "3000", $lsn3);
+	"recovery_target = 'immediate'",
+    "recovery_target_time = '$recovery_time'",);
+test_recovery_multiple_targets('multi time', 'standby_7', $node_master, \@recovery_params);
 @recovery_params = (
-	"recovery_target_time = '$recovery_time'",
-	"recovery_target_name = '$recovery_name'",
-	"recovery_target_xid  = '$recovery_txid'");
-test_recovery_standby('time + name + XID',
-	'standby_7', $node_master, \@recovery_params, "2000", $lsn2);
+	"recovery_target = 'immediate'",
+    "recovery_target_name = '$recovery_name'",);
+test_recovery_multiple_targets('multi name', 'standby_8', $node_master, \@recovery_params);
 @recovery_params = (
-	"recovery_target_xid  = '$recovery_txid'",
-	"recovery_target_time = '$recovery_time'",
-	"recovery_target_name = '$recovery_name'");
-test_recovery_standby('XID + time + name',
-	'standby_8', $node_master, \@recovery_params, "4000", $lsn4);
+	"recovery_target = 'immediate'",
+    "recovery_target_lsn = '$recovery_lsn'",);
+test_recovery_multiple_targets('multi LSN', 'standby_9', $node_master, \@recovery_params);
 @recovery_params = (
-	"recovery_target_xid  = '$recovery_txid'",
-	"recovery_target_time = '$recovery_time'",
-	"recovery_target_name = '$recovery_name'",
-	"recovery_target_lsn = '$recovery_lsn'",);
-test_recovery_standby('XID + time + name + LSN',
-	'standby_9', $node_master, \@recovery_params, "5000", $lsn5);
+    "recovery_target_xid  = '$recovery_txid'",
+    "recovery_target = 'immediate'",);
+test_recovery_multiple_targets('multi immediate', 'standby_10', $node_master, \@recovery_params);