commit bd18dda9be5ab0341eca81de3c48ec6f7466dded
Author: Masahiko Sawada <sawada.mshk@gmail.com>
Date:   Fri Sep 16 15:32:24 2016 -0700

    Change syntax

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index cd66abc..f0f510c 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -3037,7 +3037,7 @@ include_dir 'conf.d'
         This parameter specifies a list of standby servers using
         either of the following syntaxes:
 <synopsis>
-<replaceable class="parameter">num_sync</replaceable> ( <replaceable class="parameter">standby_name</replaceable> [, ...] )
+FIRST <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="parameter">standby_name</replaceable> [, ...] )
 <replaceable class="parameter">standby_name</replaceable> [, ...]
 </synopsis>
         where <replaceable class="parameter">num_sync</replaceable> is
@@ -3048,7 +3048,9 @@ include_dir 'conf.d'
         <literal>3 (s1, s2, s3, s4)</> makes transaction commits wait
         until their WAL records are received by three higher-priority standbys
         chosen from standby servers <literal>s1</>, <literal>s2</>,
-        <literal>s3</> and <literal>s4</>.
+        <literal>s3</> and <literal>s4</>. <literal>FIRST</> is
+        case-insensitive but the standby having name <literal>FIRST</>
+        must be double-quoted.
         </para>
         <para>
         The second syntax was used before <productname>PostgreSQL</>
diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml
index 06f49db..84ccb6e 100644
--- a/doc/src/sgml/high-availability.sgml
+++ b/doc/src/sgml/high-availability.sgml
@@ -1150,7 +1150,7 @@ primary_slot_name = 'node_a_slot'
     An example of <varname>synchronous_standby_names</> for multiple
     synchronous standbys is:
 <programlisting>
-synchronous_standby_names = '2 (s1, s2, s3)'
+synchronous_standby_names = 'FIRST 2 (s1, s2, s3)'
 </programlisting>
     In this example, if four standby servers <literal>s1</>, <literal>s2</>,
     <literal>s3</> and <literal>s4</> are running, the two standbys
diff --git a/src/backend/replication/Makefile b/src/backend/replication/Makefile
index c99717e..da8bcf0 100644
--- a/src/backend/replication/Makefile
+++ b/src/backend/replication/Makefile
@@ -26,7 +26,7 @@ repl_gram.o: repl_scanner.c
 
 # syncrep_scanner is complied as part of syncrep_gram
 syncrep_gram.o: syncrep_scanner.c
-syncrep_scanner.c: FLEXFLAGS = -CF -p
+syncrep_scanner.c: FLEXFLAGS = -CF -p -i
 syncrep_scanner.c: FLEX_NO_BACKUP=yes
 
 # repl_gram.c, repl_scanner.c, syncrep_gram.c and syncrep_scanner.c
diff --git a/src/backend/replication/syncrep_gram.y b/src/backend/replication/syncrep_gram.y
index 35c2776..b6d2f6c 100644
--- a/src/backend/replication/syncrep_gram.y
+++ b/src/backend/replication/syncrep_gram.y
@@ -46,7 +46,7 @@ static SyncRepConfigData *create_syncrep_config(const char *num_sync,
 	SyncRepConfigData *config;
 }
 
-%token <str> NAME NUM JUNK
+%token <str> NAME NUM JUNK FIRST
 
 %type <config> result standby_config
 %type <list> standby_list
@@ -61,7 +61,7 @@ result:
 
 standby_config:
 		standby_list				{ $$ = create_syncrep_config("1", $1); }
-		| NUM '(' standby_list ')'	{ $$ = create_syncrep_config($1, $3); }
+		| FIRST NUM '(' standby_list ')'	{ $$ = create_syncrep_config($1, $4); }
 	;
 
 standby_list:
@@ -70,7 +70,7 @@ standby_list:
 	;
 
 standby_name:
-		NAME						{ $$ = $1; }
+		NAME						{ $$ = $1;}
 		| NUM						{ $$ = $1; }
 	;
 %%
diff --git a/src/backend/replication/syncrep_scanner.l b/src/backend/replication/syncrep_scanner.l
index d20662e..9dbdfbc 100644
--- a/src/backend/replication/syncrep_scanner.l
+++ b/src/backend/replication/syncrep_scanner.l
@@ -64,6 +64,11 @@ xdinside		[^"]+
 %%
 {space}+	{ /* ignore */ }
 
+first		{
+				yylval.str = pstrdup(yytext);
+				return FIRST;
+		}
+
 {xdstart}	{
 				initStringInfo(&xdbuf);
 				BEGIN(xd);