On Fri, Sep 15, 2006 at 10:01:19AM +0100, Heikki Linnakangas wrote:
> Gregory Stark wrote:
> >It's limited but I wouldn't say it's very limiting. In the cases where it
> >doesn't apply there's no way out anyways. A UTF8 field will need a length
> >header in some form.
>
> Actually, you can determine the length of a UTF-8 encoded character by
> looking at the most significant bits of the first byte. So we could
> store a UTF-8 encoded CHAR(1) field without any additional length header.
Except in postgres the length of a datum is currently only determined
from the type, or from a standard varlena header. Going down the road
of having to call type specific length functions for the values in
columns 1 to n-1 just to read column n seems like a really bad idea.
We want to make access to later columns *faster* not slower, which
means keeping to the simplest (code-wise) scheme possible.
Have a nice day,
--
Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.
