Tom Lane wrote:
Bruce Momjian <pgman@candle.pha.pa.us> writes:
I don't think we can accept a change that takes a negative and turns it
into a positive and negative.
Yeah, I find the patch's changes to the regression results pretty
disturbing.
Perhaps the correct definition ought to be like "if month part >= 0
then the reduced day part should be between 0 and 30, otherwise the
reduced day part should be between 0 and -30". However there are
still corner cases to worry about. If the original month and day
parts are of different sign, you might not be able to do such a
reduction without changing the sign of the month part, consider
"1 month -95 days". Not clear what to do with this.
I guess I would expect a good result to satisfy one of these three
cases:
* month > 0 and 0 <= day < 30
* month < 0 and -30 < day <= 0
* month = 0 and -30 < day < 30
If you believe that then "1 month -95 days" should justify to
"-2 months -5 days".
regards, tom lane
How would you expect justify_hours to behave? I extrapolate from your rules
above that:
* month > 0 and 0 <= day < 30 and 0 <= hours < 24
* month < 0 and -30 < day <= 0 and -24 < hours <= 0
* month = 0 and -30 < day <= 0 and -24 < hours <= 0
* month = 0 and 0 <= day < 30 and 0 <= hours < 24
Which would mean that '1 month -95 days -12 hours' should justify to "-2 months
-5 days -12 hours" rather than "-2 months -6 days 12 hours", but that '1 month
-15 days -12 hours" would justify to '14 days 12 hours' rather than '15 days -12
hours'.
Is this correct?
mark
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