diff --git a/contrib/pg_upgrade/server.c b/contrib/pg_upgrade/server.c
index ed67759..c1d8d69 100644
*** a/contrib/pg_upgrade/server.c
--- b/contrib/pg_upgrade/server.c
*************** check_pghost_envvar(void)
*** 300,306 ****
  	/* Get valid libpq env vars from the PQconndefaults function */
  
  	start = PQconndefaults();
! 
  	for (option = start; option->keyword != NULL; option++)
  	{
  		if (option->envvar && (strcmp(option->envvar, "PGHOST") == 0 ||
--- 300,309 ----
  	/* Get valid libpq env vars from the PQconndefaults function */
  
  	start = PQconndefaults();
! 	if (start == NULL)
! 	{
! 		pg_log(PG_FATAL,"can not get default connection options out of memory\n");
! 	}
  	for (option = start; option->keyword != NULL; option++)
  	{
  		if (option->envvar && (strcmp(option->envvar, "PGHOST") == 0 ||
diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index eea9c6b..0a9a29e 100644
*** a/src/interfaces/libpq/fe-connect.c
--- b/src/interfaces/libpq/fe-connect.c
*************** static PQconninfoOption *conninfo_array_
*** 347,353 ****
  					 const char *const * values, PQExpBuffer errorMessage,
  					 bool use_defaults, int expand_dbname);
  static bool conninfo_add_defaults(PQconninfoOption *options,
! 					  PQExpBuffer errorMessage);
  static PQconninfoOption *conninfo_uri_parse(const char *uri,
  				   PQExpBuffer errorMessage, bool use_defaults);
  static bool conninfo_uri_parse_options(PQconninfoOption *options,
--- 347,354 ----
  					 const char *const * values, PQExpBuffer errorMessage,
  					 bool use_defaults, int expand_dbname);
  static bool conninfo_add_defaults(PQconninfoOption *options,
! 								  PQExpBuffer errorMessage,
! 								  bool ignore_missing_service);
  static PQconninfoOption *conninfo_uri_parse(const char *uri,
  				   PQExpBuffer errorMessage, bool use_defaults);
  static bool conninfo_uri_parse_options(PQconninfoOption *options,
*************** PQconndefaults(void)
*** 875,881 ****
  	connOptions = conninfo_init(&errorBuf);
  	if (connOptions != NULL)
  	{
! 		if (!conninfo_add_defaults(connOptions, &errorBuf))
  		{
  			PQconninfoFree(connOptions);
  			connOptions = NULL;
--- 876,882 ----
  	connOptions = conninfo_init(&errorBuf);
  	if (connOptions != NULL)
  	{
! 		if (!conninfo_add_defaults(connOptions, &errorBuf,true))
  		{
  			PQconninfoFree(connOptions);
  			connOptions = NULL;
*************** conninfo_parse(const char *conninfo, PQE
*** 4243,4249 ****
  	 */
  	if (use_defaults)
  	{
! 		if (!conninfo_add_defaults(options, errorMessage))
  		{
  			PQconninfoFree(options);
  			return NULL;
--- 4244,4250 ----
  	 */
  	if (use_defaults)
  	{
! 		if (!conninfo_add_defaults(options, errorMessage,false))
  		{
  			PQconninfoFree(options);
  			return NULL;
*************** conninfo_array_parse(const char *const *
*** 4395,4401 ****
  	 */
  	if (use_defaults)
  	{
! 		if (!conninfo_add_defaults(options, errorMessage))
  		{
  			PQconninfoFree(options);
  			return NULL;
--- 4396,4402 ----
  	 */
  	if (use_defaults)
  	{
! 		if (!conninfo_add_defaults(options, errorMessage,false))
  		{
  			PQconninfoFree(options);
  			return NULL;
*************** conninfo_array_parse(const char *const *
*** 4416,4422 ****
   * error condition here --- we just leave the option's value as NULL.
   */
  static bool
! conninfo_add_defaults(PQconninfoOption *options, PQExpBuffer errorMessage)
  {
  	PQconninfoOption *option;
  	char	   *tmp;
--- 4417,4424 ----
   * error condition here --- we just leave the option's value as NULL.
   */
  static bool
! conninfo_add_defaults(PQconninfoOption *options, PQExpBuffer errorMessage,
! 					  bool ignore_missing_service)
  {
  	PQconninfoOption *option;
  	char	   *tmp;
*************** conninfo_add_defaults(PQconninfoOption *
*** 4425,4431 ****
  	 * If there's a service spec, use it to obtain any not-explicitly-given
  	 * parameters.
  	 */
! 	if (parseServiceInfo(options, errorMessage) != 0)
  		return false;
  
  	/*
--- 4427,4434 ----
  	 * If there's a service spec, use it to obtain any not-explicitly-given
  	 * parameters.
  	 */
! 	if (parseServiceInfo(options, errorMessage) != 0 && 
! 		! ignore_missing_service)
  		return false;
  
  	/*
*************** conninfo_uri_parse(const char *uri, PQEx
*** 4511,4517 ****
  	 */
  	if (use_defaults)
  	{
! 		if (!conninfo_add_defaults(options, errorMessage))
  		{
  			PQconninfoFree(options);
  			return NULL;
--- 4514,4520 ----
  	 */
  	if (use_defaults)
  	{
! 		if (!conninfo_add_defaults(options, errorMessage,false))
  		{
  			PQconninfoFree(options);
  			return NULL;