possible/feasible to specify field and value in error msg?

Hi,

I have some complicated query that truncates and fills a table and i get
this message:
ERROR: smallint out of range
STATEMENT: <my huge query>
This is in postgres 8.4
I don't know where the error is, and the query takes rather long. So it is
going to be a bit cumbersome for me to debug this.

Would it be possible/feasible to specify, in future versions of postgres:
* what value
* which field (of which table)
* the offending tuple? (possibly truncated to some threshold nr of
characters)

I ask because i can imagine that, inside the code that handles this, you
might not have access to that information and adding access to it might be
inefficient.

I do get the whole query of course, and that is very handy for automated
things. But in this case, it doesn't help me.

Cheers,

WBL

--
"Quality comes from focus and clarity of purpose" -- Mark Shuttleworth