Unable to handle error in plperl

Dear all,

I have a situation. I am unable to pass control back to the function
once it hit the "undefined_column" error code.
I am not sure there's a way to return '123' instead exit from the function.

Here is my code

CREATE OR REPLACE FUNCTION foo() RETURNS text as $$
my $sql = "";
my $status = "";
my $r = "";
$sql = 'SELECT non_exist_column from a_table limit 1';
eval { spi_exec_query($sql);};
if ($@) {
$status = 'invalid: '.$@;
elog(ERROR, $status);
return '123';
} else {
$status = 'valid';
}
return $status;
$$ LANGUAGE plperl;

When I run it

select foo();

ERROR: invalid: column "non_exist_column" does not exist at line 6.
CONTEXT: PL/Perl function "foo"

When I select from the valid column
CREATE OR REPLACE FUNCTION foo() RETURNS text as $$
my $sql = "";
my $status = "";
my $r = "";
$sql = 'SELECT exist_column from a_table limit 1';
eval { spi_exec_query($sql);};
if ($@) {
$status = 'invalid: '.$@;
elog(ERROR, $status);
return '123';
} else {
$status = 'valid';
}
return $status;
$$ LANGUAGE plperl;

When I run it

select foo();

foo
----------
valid
(1 row)

--
Best regards,

Alex Lai
OMI SIPS DBA ADNET Systems , Inc.
7515 Mission Drive,
Suite A100 Lanham, MD 20706
301-352-4657 (phone)
301-352-0437 (fax)
mlai(at)sesda3(dot)com