Re: proposal: enhanced stack trace for PL - print param args

On Sun, Jan 15, 2017 at 1:27 AM, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
wrote:

> Hi
>
> Proposed result:
> postgres=# select foo(0, 100);
> ERROR: division by zero
> CONTEXT: PL/pgSQL function foo(double precision) line 3 at RETURN
> ARGUMENTS: a=0, b=100
>

+1 This would be useful in cases where an app calls one procedure and then
disconnects. It's hard to know which of the thousands of invocations caused
the error.

>
> * only function parameters are printed - no local parameters
>

+1, we'd have no insight into variables inside the function anyway.

> * the line of arguments will be limited - X chars ?
>

+1

> * the content of variable should be limited - X chars ? - maybe 40 chars
>
> This function can has impact on performance - so it should be explicitly
> enabled with some GUC - like extra_back_trace or some similar. Probably
> before any call the function parameters and related out functions should be
> copied to safe memory context. More it can increase press on Error Memory
> Context and possibly on log size.
>

func_args_back_trace?