Re: Strange results when casting string to double

On Wed, Feb 16, 2022 at 11:38 AM Carsten Klein <c(dot)klein(at)datagis(dot)com> wrote:

>
>
> On Wed, Feb 16, 2022 at 05:46 PM Adrian Klaver wrote
> > On 2/16/22 05:27, Carsten Klein wrote:
> >> Hi there,
> >>
> >> I'm using several (now unsupported) PostgreSQL 9.3.24 servers on
> >> different (ancient) Ubuntu 14.04 LTS machines. On only one of those
> >> servers, I get strange/wrong results when converting a string into a
> >> double value:
> >>
> >
> >> Has anyone an idea of what's going on here? I know, this version is
> >> far from still being supported, however, there's not much real changes
> >> in file float.c between these versions (in other words, this may
> >> happen with recent versions as well?). The database instances on all
> >> servers are configured quite the same (more or less).
>
>
> > What is the more or less for the problem server?
>
> What? Didn't get that...
>

You said they are more or less the same. Problems like these tend to hide
in the "less" portion of the inequality.

> Testing System: VMware (ESX Host B) DOES NOT WORK as expected
>
>
Given that this isn't working as expected it doesn't make for a great
testing system. Install and initdb 14.2 on this machine and let's see what
PostgreSQL produces.

> > If not how does the problem server differ?
>
> I certainly have no idea. Actually, I don't see any more relevant
> differences.
>

What is the precise version of libc that is installed for one. Exact ESX
releases too.

This isn't really all that interesting a report for the project if it only
exists in one ancient system that cannot be experimented with. Maybe
it's a faulty register on that machine's CPU. There is more
double-checking and comparing that can be done here but it seems unlikely
to be productive. It is more plausible that the snowflake machine in
question just has issues and needs to be retired. Installing a newer
version of PostgreSQL on it before junking it is about the right amount of
experimental effort.

David J.