When you create a foreign table or use READ_NOS to read directly from external object storage, you must specify a key prefix as part of the USING...LOCATION parameter to identify specific data (one or more files that match the key prefix). However, the actual data queried in the external storage that correspond to the key prefix is determined when you make a foreign table query. Because data may be added or deleted to the external storage system at any time, identical queries against external storage may yield different results.