The size in bytes of each index node.

    The number and level of the resulting index nodes depend on:

    o  This number-bytes value

    o  The number and size of the index keys

    o  The value specified in the PERCENT FILL or USAGE clauses

    If you omit the NODE SIZE clause, the default value is:

    o  430 bytes if the total index key size is 120 bytes or less

    o  860 bytes if the total index key size is more than 120 bytes

    The index key size is the number of bytes it takes to represent
    the column value in the sorted index.

    See the Oracle Rdb SQL Reference Manual for details on
    determining the valid range for a user-specified index node size.