*** a/src/backend/utils/init/postinit.c
--- b/src/backend/utils/init/postinit.c
***************
*** 65,70 **** static void CheckMyDatabase(const char *name, bool am_superuser);
--- 65,71 ----
  static void InitCommunication(void);
  static void ShutdownPostgres(int code, Datum arg);
  static bool ThereIsAtLeastOneRole(void);
+ static void process_startup_options(Port *port, bool am_superuser);
  static void process_settings(Oid databaseid, Oid roleid);
  
  
***************
*** 476,482 **** InitPostgres(const char *in_dbname, Oid dboid, const char *username,
  {
  	bool		bootstrap = IsBootstrapProcessingMode();
  	bool		am_superuser;
- 	GucContext	gucctx;
  	char	   *fullpath;
  	char		dbname[NAMEDATALEN];
  
--- 477,482 ----
***************
*** 661,666 **** InitPostgres(const char *in_dbname, Oid dboid, const char *username,
--- 661,668 ----
  			ereport(FATAL,
  					(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
  					 errmsg("must be superuser to start walsender")));
+ 		/* process any options passed in the startup packet */
+ 		process_startup_options(MyProcPort, am_superuser);
  		/* report this backend in the PgBackendStatus array */
  		pgstat_bestart();
  		/* close the transaction we started above */
***************
*** 811,843 **** InitPostgres(const char *in_dbname, Oid dboid, const char *username,
  		CheckMyDatabase(dbname, am_superuser);
  
  	/*
! 	 * Now process any command-line switches that were included in the startup
! 	 * packet, if we are in a regular backend.	We couldn't do this before
  	 * because we didn't know if client is a superuser.
  	 */
  	gucctx = am_superuser ? PGC_SUSET : PGC_BACKEND;
  
! 	if (MyProcPort != NULL &&
! 		MyProcPort->cmdline_options != NULL)
  	{
  		/*
  		 * The maximum possible number of commandline arguments that could
! 		 * come from MyProcPort->cmdline_options is (strlen + 1) / 2; see
  		 * pg_split_opts().
  		 */
  		char	  **av;
  		int			maxac;
  		int			ac;
  
! 		maxac = 2 + (strlen(MyProcPort->cmdline_options) + 1) / 2;
  
  		av = (char **) palloc(maxac * sizeof(char *));
  		ac = 0;
  
  		av[ac++] = "postgres";
  
! 		/* Note this mangles MyProcPort->cmdline_options */
! 		pg_split_opts(av, &ac, MyProcPort->cmdline_options);
  
  		av[ac] = NULL;
  
--- 813,887 ----
  		CheckMyDatabase(dbname, am_superuser);
  
  	/*
! 	 * Now process any command-line switches and any additional GUC variable
! 	 * settings passed in the startup packet.	We couldn't do this before
  	 * because we didn't know if client is a superuser.
  	 */
+ 	process_startup_options(MyProcPort, am_superuser);
+ 
+ 	/* Process pg_db_role_setting options */
+ 	process_settings(MyDatabaseId, GetSessionUserId());
+ 
+ 	/* Apply PostAuthDelay as soon as we've read all options */
+ 	if (PostAuthDelay > 0)
+ 		pg_usleep(PostAuthDelay * 1000000L);
+ 
+ 	/*
+ 	 * Initialize various default states that can't be set up until we've
+ 	 * selected the active user and gotten the right GUC settings.
+ 	 */
+ 
+ 	/* set default namespace search path */
+ 	InitializeSearchPath();
+ 
+ 	/* initialize client encoding */
+ 	InitializeClientEncoding();
+ 
+ 	/* report this backend in the PgBackendStatus array */
+ 	if (!bootstrap)
+ 		pgstat_bestart();
+ 
+ 	/* close the transaction we started above */
+ 	if (!bootstrap)
+ 		CommitTransactionCommand();
+ }
+ 
+ /*
+  * Process any command-line switches and any additional GUC variable
+  * settings passed in the startup packet.
+  */
+ static void
+ process_startup_options(Port *port, bool am_superuser)
+ {
+ 	GucContext	gucctx;
+ 
+ 	/*
+ 	 * Now process any command-line switches that were included in the startup
+ 	 * packet, if we are in a regular backend.
+ 	 */
  	gucctx = am_superuser ? PGC_SUSET : PGC_BACKEND;
  
! 	if (port != NULL &&
! 		port->cmdline_options != NULL)
  	{
  		/*
  		 * The maximum possible number of commandline arguments that could
! 		 * come from port->cmdline_options is (strlen + 1) / 2; see
  		 * pg_split_opts().
  		 */
  		char	  **av;
  		int			maxac;
  		int			ac;
  
! 		maxac = 2 + (strlen(port->cmdline_options) + 1) / 2;
  
  		av = (char **) palloc(maxac * sizeof(char *));
  		ac = 0;
  
  		av[ac++] = "postgres";
  
! 		/* Note this mangles port->cmdline_options */
! 		pg_split_opts(av, &ac, port->cmdline_options);
  
  		av[ac] = NULL;
  
***************
*** 850,858 **** InitPostgres(const char *in_dbname, Oid dboid, const char *username,
  	 * Process any additional GUC variable settings passed in startup packet.
  	 * These are handled exactly like command-line variables.
  	 */
! 	if (MyProcPort != NULL)
  	{
! 		ListCell   *gucopts = list_head(MyProcPort->guc_options);
  
  		while (gucopts)
  		{
--- 894,902 ----
  	 * Process any additional GUC variable settings passed in startup packet.
  	 * These are handled exactly like command-line variables.
  	 */
! 	if (port != NULL)
  	{
! 		ListCell   *gucopts = list_head(port->guc_options);
  
  		while (gucopts)
  		{
***************
*** 868,899 **** InitPostgres(const char *in_dbname, Oid dboid, const char *username,
  			SetConfigOption(name, value, gucctx, PGC_S_CLIENT);
  		}
  	}
- 
- 	/* Process pg_db_role_setting options */
- 	process_settings(MyDatabaseId, GetSessionUserId());
- 
- 	/* Apply PostAuthDelay as soon as we've read all options */
- 	if (PostAuthDelay > 0)
- 		pg_usleep(PostAuthDelay * 1000000L);
- 
- 	/*
- 	 * Initialize various default states that can't be set up until we've
- 	 * selected the active user and gotten the right GUC settings.
- 	 */
- 
- 	/* set default namespace search path */
- 	InitializeSearchPath();
- 
- 	/* initialize client encoding */
- 	InitializeClientEncoding();
- 
- 	/* report this backend in the PgBackendStatus array */
- 	if (!bootstrap)
- 		pgstat_bestart();
- 
- 	/* close the transaction we started above */
- 	if (!bootstrap)
- 		CommitTransactionCommand();
  }
  
  /*
--- 912,917 ----