Re: Add column name to error message?

Em 18/03/2014 17:44, Tom Lane escreveu:
> Edson Richter <edsonrichter(at)hotmail(dot)com> writes:
>> Em 18/03/2014 17:17, Francisco Olarte escreveu:
>>> Maybe they are not hiding it, but the error is raised by a value
>>> checking routine which does not know where the value comes from / goes
>>> to ( ie, it's a 'check_varchar(xx, maxlen), which is used to check
>>> columns, function aprameters, type casts....) ( that happens to me in
>>> my own code in some places where the context / error message is
>>> extremely difficult to propagate down / up ) .
>> Thanks, Francisco. I don't know internals.
>> But, doesn't the "value checking routing" caller's know which column is
>> being tested?
> No. Typically all it would know is that it's evaluating a targetlist; the
> fact that the resulting tuple is going to be inserted into some particular
> table is known only at much higher levels (not even the same plan node).
>
> I've thought about using our "errcontext()" mechanism to help with this,
> but there's still a lot of additional infrastructure that would be needed
> ... and that infrastructure would not be without cost. I'm afraid it
> would result in measurable slowdowns in query execution. Not sure if
> people would think that's a good tradeoff.
>
> regards, tom lane
>
>
Thanks, Tom.
I don't know much about Postgres source code. I was wondering if it
works like in Java apps, where the exception thrown is capture by higher
layer until having enough information to provide complete erros message
to the user (being a user a real user or kind of interface - jdbc or
odbc - user).

Now I understand better, and I'm also afraid of getting slowdown. I do
prefer the higher performance at price of having to discover the right
problem on my own.

Regards,

Edson