Re: Function trunc() behaves in unexpected manner with different data types - Mailing list pgsql-bugs

Merlin Moncure <mmoncure@gmail.com> writes:
> right -- in understand how floating point works -- but are you are
> saying that you are ok with the fact that (for example) a table with a
> floating point unique key could dump and not restore? more
> specifically, a binary dump would restore but a text dump would not.

pg_dump takes measures against that (see extra_float_digits).

> I think this is a problem with our implementation -- not all versions
> of 2183.68 as outputted from the server are the same internally.

It's an inherent property of float math.  Yes, we could set the default
value of extra_float_digits high enough that distinct internal values
always had distinct text representations, but trust me, you would not
like it.

            regards, tom lane