Re: Is pgAdmin the only front-end to PostgreSQL debugger ? And is "a working pl/pgsql debugger" something core should care to maintain ?

Hi

pá 14. 2. 2025 v 0:37 odesílatel Hannu Krosing <hannuk(at)google(dot)com> napsal:

> On Thu, Feb 13, 2025 at 8:10 PM Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
> wrote:
> >
> > Hi
> >
> > čt 13. 2. 2025 v 18:00 odesílatel Hannu Krosing <hannuk(at)google(dot)com>
> napsal:
> >>
> >> Hallo PostgreSQL Hackers,
> >>
> >>
> >> We recently discovered an error where pgAdmin fails when stepping into
> >> nested function calls (
> >> https://github.com/pgadmin-org/pgadmin4/issues/8443 ).
> >>
> >> So while waiting for this to be fixed I would want to know if there
> >> are other debugger front-ends that could be used to do basic debugging
> >> of pl/pgsql code ?
> >
> >
> > If I remember, there was a independent application that was a plpgsql
> debugger, but it was in time before pgadmin 4
> >
> ...
> >> Should there perhaps be debugging support in psql ?
> >
> > psql does not support asynchronous API, so the implementation in psql
> really should not be simple. Moreover,
> > I doubt that users want to use a debugger with a GUI similar to gdb.
>
> It would be good to have some simple fallback in case the shiny GUI
> things don't work.
>
> For example python has its pdb module and node.js has a "debugging
> mode" where you can set breakpoints and single-step through your code.
>

Minimally in psql, you cannot do anything until the query is ended.
PLdebugger allows debugging from a separate session, and implements its own
network protocol. This can be a possible security issue. When PLdebugger is
not installed, then there is not a security risk.

So the support in psql is not a small change. plpgsql_check supports
tracing, plpgsql byself supports RAISE NOTICE. I think it is enough for
these old school developers.
Can be nice to do something better, but there are no customers. Probably,
there can be nicer features for psql - like supports some richer scripting,
maybe lua or similar language, custom commands, custom reports, etc.

It would be nice to debug the plpgsql function inside a gdb like C
function, but probably it is not possible.

> > And it isn't possible to design a better UI directly in psql. I can
> imagine supporting some external debuggers executed inside / or outside the
> same terminal that communicates with psql by some bidirect pipe (psql will
> be used like a proxy). Then can be designed some application similar to
> Borland debugger. This can be a very nice feature with probably not too
> much code, but handling bidirect pipes isn't trivial. Tuning reading from
> pipe for pspg for some less usual patterns was not nice work (and there the
> communication is significantly more simple than for debugger).
>
> So a possibly better way could be adding pl/pgsql debugging support to
> something widely used like VSCode ?
>

surely. I found
https://kichwacoders.com/2017/07/28/what-about-a-common-debug-protocol/

I don't have enough knowledge in this area, but I think there can be
support for gdb or maybe other common projects, and then debugging can be
possible from vi, emacs for dinosaurs like me, or from eclipse, dbeaver,
vscode for people.

Regards

Pavel

>
> --
> Hannu
>