not perform SDataRow/SKVRow convert anymore, utilize boundNullLen to facilitate the memRowType predict

specify child table name instead using ID in tag field.

user pass timestamp precision for line protocol, openTSDB related
timestamp accpet only 10 digits(second) or 13 digits(millisecond) by
default

length(<=64) boundaries.

JSON numbers.
Interger number -> BIGINT (contains only digits and '+' '-')
Floating number -> DOUBLE (including decimal point format or scientific
notation format)