Re: binary protocol was Performance problem with timestamps in result sets

"Thomas Dudziak" <tomdzk@gmail.com> writes:

> On 3/9/06, mikael-aronsson <mikael-aronsson@telia.com> wrote:
>> How about the actual transport cost difference between text and binary
>> protocols ? it may not be any big difference though, and many times text
>> representation can be smaller then a binary protocol.
>
> Really ? I would have thought its vice versa. E.g. a float is usualy 4
> (or 8) bytes in binary, but can be a lot longer in text depending on
> the format.


To represent binary IEEE754's floats (4 bytes) without loss the
maximum required number of base10 digits is 9. For IEEE754's doubles
(8 bytes) it's 17. I don't know what is the "average" required number
of digits.


Of course using one byte-character per base10 digit is a waste of
space... you could gzip or BCD-encode the string :-)

References:
- "What Every Computer Scientist Should Know About Floating Point
Arithmetic" 1991 - David Goldberg
- paragraph "Conversions" at:
<http://www2.hursley.ibm.com/decimal/>