NUMERIC data type is hardcoded to use '.' as the decimal point.
FLOATs are in fact hardcoded the same way (they use strtod() and sprintf()
while pgsql's LC_NUMERIC is always "C").
The only data type that localizes decimal point is MONEY.
it makes many problems when the decimal point is not '.' (for example, ',').
is it a bug or a feature?