*** a/src/backend/utils/adt/xml.c
--- b/src/backend/utils/adt/xml.c
***************
*** 1627,1632 **** map_sql_value_to_xml_value(Datum value, Oid type)
--- 1627,1633 ----
  					if (DATE_NOT_FINITE(date))
  						ereport(ERROR,
  								(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
+ 								 errdetail("XML does not support infinite date values."),
  								 errmsg("date out of range")));
  					j2date(date + POSTGRES_EPOCH_JDATE,
  						   &(tm.tm_year), &(tm.tm_mon), &(tm.tm_mday));
***************
*** 1649,1654 **** map_sql_value_to_xml_value(Datum value, Oid type)
--- 1650,1656 ----
  					if (TIMESTAMP_NOT_FINITE(timestamp))
  						ereport(ERROR,
  								(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
+ 								 errdetail("XML does not support infinite timestamp values."),
  								 errmsg("timestamp out of range")));
  					else if (timestamp2tm(timestamp, NULL, &tm, &fsec, NULL, NULL) == 0)
  						EncodeDateTime(&tm, fsec, NULL, &tzn, USE_XSD_DATES, buf);
***************
*** 1675,1680 **** map_sql_value_to_xml_value(Datum value, Oid type)
--- 1677,1683 ----
  					if (TIMESTAMP_NOT_FINITE(timestamp))
  						ereport(ERROR,
  								(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
+ 								 errdetail("XML does not support infinite timestamp values."),
  								 errmsg("timestamp out of range")));
  					else if (timestamp2tm(timestamp, &tz, &tm, &fsec, &tzn, NULL) == 0)
  						EncodeDateTime(&tm, fsec, &tz, &tzn, USE_XSD_DATES, buf);