How to find what data caused Oracle function failure? - sql

Question

sorry if this not the right place.
I am doing a SQL SELECT statement, invoking a function. It's a large data dump - about 10,000 records.
I am calling a function to preform some calculations, but its failing.
One ore more of those records has bad data that is causing the function to crash.
Is there any way to see exactly what data caused the crash readily Or should I create some code to run the function by hand for each of 10,000 records? I could create code that generates the input data fairly straightforwardly, then run the function like this SELECT MY_FUNCT(1,1,1) FROM DUAL; but I am wondering if there is a better way.
For reference I am running the SQL query like this.
SELECT
MY_FUNCT(A.FOO, A.BAR)
FROM TABLE A
WHERE ....;

Answer 1

As others have said, you just need to handle the error and not raise it all the way. A neat way of doing this would be to create a wrapper function for your function that sometimes fails, you can declare this function within your select query using a with pl/sql clause:
Let's say this is your function that sometimes fails
create or replace function my_funct (inputnumber number)
return varchar2
is
sString varchar2(200);
begin
if inputnumber = 42 then
raise_application_error(-20001,'UH OH!');
end if;
sString := 'Input: '||inputnumber;
return sString;
end my_funct;
/
We can define a function that takes the same inputs, and just calls this function, then we just need to add some error handling (obviously never just rely on dbms_output to capture errors, this is just to make it obvious):
function my_funct_handle (inputnumber number)
return varchar2
is
begin
return my_funct (inputnumber => inputnumber);
exception when others then
dbms_output.put_line(sqlerrm||' at '||inputnumber);
return 'ERROR';
end;
And we can then just stick that in our query using with function
with
function my_funct_handler (inputnumber number)
return varchar2
is
begin
return my_funct (inputnumber => inputnumber);
exception when others then
dbms_output.put_line(sqlerrm||' at '||inputnumber);
return 'ERROR';
end;
select my_funct_handler (id), string_col
from as_table;
/
I get both the dbms_output text to describe the error and the ID but I could also filter on the results of that function to only show me the erroring rows:
with
function my_funct_handle (inputnumber number)
return varchar2
is
begin
return my_funct (inputnumber => inputnumber);
exception when others then
dbms_output.put_line(sqlerrm||' at '||inputnumber);
return 'ERROR';
end;
select my_funct_handle (id), string_col
from as_table
where my_funct_handle (id) = 'ERROR';
/
MY_FUNCT_HANDLE(ID)
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
STRI
----
ERROR
blah
ORA-20001: UH OH! at 42
ORA-20001: UH OH! at 42
(I get two errors shown in the dbms_output output as the function can be called multiple times - once as part of the select list and once as part of the where clause.)

Answer 2

One option is to handle the exception properly, e.g.
create or replace function my_funct(par_foo in number, par_bar in number)
return number
is
retval number;
begin
select sal
into retval
from emp
where ename = par_foo
and deptno = par_bar;
return par_foo/par_bar;
exception --> this
when no_data_found then
return null;
end;
If you want, you can even log those errors. How? Make the function autonomous transaction (so that it could write into the log table; you'll have to commit that insert). Store all relevant information (including SQLERRM). Once your code finishes, check what's written in the log file and then decide what to do.
Or, you could even continue current task by enclosing that select into its own begin-exception-end block within a loop, e.g.
begin
for cur_r in (select ... from ...) loop
begin
-- your current SELECT
SELECT
MY_FUNCT(A.FOO, A.BAR)
FROM TABLE A
WHERE ....;
exception
when others then
dbms_output.put_line(cur_r.some_value ||': '|| sqlerrm);
end;
end loop;
end;

Answer 3

one better approach is to create a error handler Package/Procedure which will write it into a table and call it from the function, this way all the errors will be captured in a Oracle table.
--- untested -- You can create other columns to capture the function name, date, and other details in the error table.
PROCEDURE SP_ERROR_INS_ERR_COMMON (n_ERR_CODE NUMBER, c_ERR_SOURCE VARCHAR2, n_ERR_LINE NUMBER, c_ERR_DESC VARCHAR2, C_USER_COMMENT VARCHAR2 ) IS
n_Log_Id NUMBER;
PRAGMA AUTONOMOUS_TRANSACTION;
BEGIN
n_Log_Id := 0;
INSERT INTO ERROR_LOG_COMMON
(ERROR_CODE, ERROR_SOURCE, ERROR_LINE, ERROR_DESCRIPTION, USER_COMMENT)
VALUES
(n_ERR_CODE, c_ERR_SOURCE, n_ERR_LINE, c_ERR_DESC, C_USER_COMMENT
);
COMMIT;
raise_application_error( -20001,SUBSTR(SQLERRM, 1, 200));
END SP_ERROR_INS_ERR_COMMON;
In your function you can call the error
EXCEPTION
WHEN OTHERS
THEN
vn_errcode := SQLCODE;
vc_errmsg := SUBSTR (SQLERRM, 1, 4000);
sp_error_ins_err_common(vn_ErrCode,
'SP_RP_DIM_COMPARE', NULL, vc_ErrMsg, substr('batch_id ' || g_BATCH_ID ||
l_str_err_msg,1,4000) );
RAISE;