In addition to the bulk load data file, DataDirect Bulk Load can store bulk data in external overflow files. These overflow files are located in the same directory as the bulk load data file. Different files are used for binary data and character data. Whether or not to use external overflow files is a performance consideration. For example, binary data is stored as hexadecimal-encoded character strings in the main bulk load data file, which increases the size of the file per unit of data stored. External files do not store binary data as hex character strings, and, therefore, require less space. On the other hand, more overhead is required to access external files than to access a single bulk load data file, so each bulk load situation must be considered individually.