The LOGFILE clause names the file that contains messages generated by the external tables utility while it was accessing data in the data file. If a log file already exists by the same name, then the access driver reopens that log file and appends new log information to the end. This is different from bad files and discard files, which overwrite any existing file. The NOLOGFILE clause is used to prevent creation of a log file.
If you specify LOGFILE, then you must supply either a directory object name or file name, or both. See "[directory object name:] [filename]".
If neither LOGFILE nor NOLOGFILE is specified, then the default is to create a log file. The name of the file will be the table name followed by _%p and it will have an extension of .log.