Re: proposal: rounding up time value less than its unit.

Peter Eisentraut-2 wrote
> On 8/21/14 11:16 AM, Tom Lane wrote:
>> Heikki Linnakangas <

> hlinnakangas@

> > writes:
>>> The patch also rounds a zero up to one. A naked zero with no unit is not
>>> affected, but e.g if you have "log_rotation_age=0s", it will not disable
>>> the feature as you might expect, but set it to 1 minute. Should we do
>>> something about that?
>>
>> That sounds like a dealbreaker to me. There are enough places where zero
>> has special meaning that we should not *ever* change zero to non-zero
>> silently.
>
> I don't think I like this idea anyway. If something has units of an
> hour and the user (perhaps misunderstanding the setting) sets it to one
> second, then we shouldn't silently change that to one hour.
>
> If there is a problem with rounding it to zero, then we should perhaps
> raise an error. (And stop treating zero specially. It's a terrible
> idea.)

I'm on board, from the original thread, for errors if the input cannot be
converted to the parameter measurement unit cleanly. By which I mean the
specified value should result in an integer being recorded without rounding.
Specifying a precision less than the default unit thus becomes impossible.

I don't have a problem with zero meaning disabled when appropriate since it
avoids having a separate on/off GUC.

That said the complaint here just seems like a bug in the supplied patch -
zero is zero regardless of whether a unit is specified. The only obvious
exception would be temperature but that isn't relevant here.

David J.

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