Re: seeming overflow during avg() of intervals without errors/warnings - Mailing list pgsql-general

From Tom Lane
Subject Re: seeming overflow during avg() of intervals without errors/warnings
Date
Msg-id 26350.1368629441@sss.pgh.pa.us
Whole thread Raw
In response to seeming overflow during avg() of intervals without errors/warnings  (Vick Khera <vivek@khera.org>)
Responses Re: seeming overflow during avg() of intervals without errors/warnings
List pgsql-general
Vick Khera <vivek@khera.org> writes:
> So basically, it seems like however avg() on intervals is being computed it
> is overflowing somewhere without warning.

Hmmm ... yeah, it looks like interval_pl is missing any overflow check:

regression=# select '2147483648 days'::interval;
ERROR:  interval field value out of range: "2147483648 days"
LINE 1: select '2147483648 days'::interval;
               ^
regression=# select '2147483647 days'::interval;
    interval
-----------------
 2147483647 days
(1 row)

regression=# select '2147483647 days'::interval + '1 day'::interval;
     ?column?
------------------
 -2147483648 days
(1 row)

Somebody ought to fix that.

A larger question is whether it'd be worth the trouble for interval
avg() to use some wider internal representation so it could avoid
the overflow.  Given the lack of prior complaints I'm inclined to
suspect it's not.

            regards, tom lane


pgsql-general by date:

Previous
From: Merlin Moncure
Date:
Subject: Re: Re: volatile void returning function not executed as often as expected in sql function
Next
From: Jorge Arévalo
Date:
Subject: Best way to reduce server rounds getting big BLOBs