Re: System views for versions reporting

> On Sun, Oct 06, 2024 at 12:01:29PM GMT, Joe Conway wrote:
> On 10/6/24 11:36, Dmitry Dolgov wrote:
> > Hi,
> >
> > Based on the feedback in [1], here is my attempt at implementing system
> > views for versions reporting. It adds pg_system_versions for showing
> > things like core version, compiler, LLVM, etc, and pg_system_libraries
> > for showing linked shared objects. I think everyone has ageed that the
> > first was a good idea, where the second was only suggested -- after some
> > thinking I find shared obects useful enough to include here as well.
> >
> > The main idea is to facilitate bug reporting. In particular, in many JIT
> > related bug reports one of the first questions is often "which LLVM
> > version is used?". Gathering such information is a manual process,
> > mistakes could be made when veryfing llvm-config output or anywhere
> > else. Having a system view for such purposes makes the process a bit
> > more robust.
> >
> > The first three patches are essential for this purpose, the fourth one
> > is somewhat independent and could be concidered in isolation. The output
> > looks like this :
> >
> > =# select * from pg_system_versions;
> > name | version | type
> > ----------+--------------+--------------
> > Arch | x86_64-linux | Compile Time
> > ICU | 15.1 | Compile Time
> > Core | 18devel | Compile Time
> > Compiler | gcc-14.0.1 | Compile Time
> > LLVM | 18.1.6 | Run Time
>
> I'm not sure why ICU is "Compile Time" rather than "Run Time" when it is not
> statically linked.

It reports U_UNICODE_VERSION at compile time. It's not necessarily
correct though, I can try to replace it with the runtime version. I
think there was some ICU functionality (something like
u_getUnicodeVersion), which is maybe a better fit.

> Also, if we are going to include ICU here, shouldn't we
> also include libc version?

Yeah, why not. One of my goals here is to identify a balanced set of
useful versions to report.

> > =# select * from pg_system_libraries;
> > name
> > -----------------------------
> > /lib64/libkrb5.so.3
> > /lib64/libz.so.1
> > linux-vdso.so.1
> > /lib64/libxml2.so.2
> > [...]
> >
> > Any feedback is appreciated.
>
> I think it would be nice to include a sha256 hash (or something similar) of
> the libraries as well, so that they can be checked against known good
> values.

I was thinking about getting more info to show in this view, but haven't
found any reasonable way to achieve that. So I would agree with Tom on
that.