Re: float output precision questions

Pedro Miguel Frazao Fernandes Ferreira writes:

> Is there a way to set query output precision to maximum precision ?
> For the type of application I mentioned this is crucial. People want to
> get the 'same' numbers, from querys or dumps, as they inserted them.

There isn't a way right now, but it's planned to be able to dump
floating-point numbers in some binary form (like printf("%A")) to be able
to restore them exactly. Not sure how that would satisfy the needs of
client interfaces, though.

> Matlab has a toolbox fucntion, claiming maximum precision, to convert
> from its double type (PostgreSQL float8) to string which does a
> sprintf('%25.18g',number).

Do we have some mathematical guarantee that this is sufficient and
necessary? If so, then it might do.

--
Peter Eisentraut peter_e(at)gmx(dot)net