Fabrice Chapuis <fabrice636861@gmail.com> writes:
> Documentation says:
> double precision 8 bytes variable-precision, inexact 15 decimal digits
> precision
The documentation is stating the minimum number of decimal digits
that will be accurately reproduced. You got 16 reproduced correctly
in this example, but you were lucky.
float8out has a different rule, which is to emit enough digits to
describe the actually-stored binary value unambiguously, so that
dump and reload will not change the stored value.
regards, tom lane