Re: [PATCH] expand the units that pg_size_pretty supports on output - Mailing list pgsql-hackers

On Tue, 6 Jul 2021 at 10:20, David Rowley <dgrowleyml@gmail.com> wrote:
>
> I made another pass over this and ended up removing the doHalfRound
> field in favour of just doing rounding based on the previous
> bitshifts.
>

When I first read this:

+            /* half-round until we get down to unitBits */
+            while (rightshifts++ < unit->unitBits)
+                size = half_rounded(size);

it looked to me like it would be invoking half_rounded() multiple
times, which raised alarm bells because that would risk rounding the
wrong way. Eventually I realised that by the time it reaches that,
rightshifts will always equal unit->unitBits or unit->unitBits - 1, so
it'll never do more than one half-round, which is important.

So perhaps using doHalfRound would be clearer, but it could just be a
local variable tracking whether or not it's the first time through the
loop.

Regards,
Dean