Default: operating system-dependent
The integer specified for BUFFER is the size, in bytes, of the buffer through which data rows are transferred.
BUFFER determines the number of rows in the array inserted by Import. The following formula gives an approximation of the buffer size that inserts a given array of rows:
buffer_size = rows_in_array * maximum_row_size
For tables containing LOBs, LONG, BFILE, REF, ROWID,UROWID, or TIMESTAMP columns, rows are inserted individually. The size of the buffer must be large enough to contain the entire row, except for LOB and LONG columns. If the buffer cannot hold the longest row in a table, then Import attempts to allocate a larger buffer.
For DATE columns, two or more rows are inserted at once if the buffer is large enough.