Adding function to Oracle is not permament - oracle

Question

I am experiencing weird behavior of Oracle Database 19c. I created user-defined function named raw_to_guid in SqlDeveloper for user 'TEST'. Content of this function is not important really because it's compiling successfully but just in case I share with code below.
create or replace function raw_to_guid( raw_guid in raw ) return varchar2
is
hex varchar2(32);
begin
hex := rawtohex(raw_guid);
return substr(hex, 7, 2)
|| substr(hex, 5, 2)
|| substr(hex, 3, 2)
|| substr(hex, 1, 2)
|| '-'
|| substr(hex, 11, 2)
|| substr(hex, 9, 2)
|| '-'
|| substr(hex, 15, 2)
|| substr(hex, 13, 2)
|| '-'
|| substr(hex, 17, 4)
|| '-'
|| substr(hex, 21, 12);
end
Next step is establish connection to Oracle database from my app and provide login data for user 'TEST'. I have several SELECT statements which use function raw_to_guid and all works perfectly fine.
Now is the clue of my problem:
For first 3-4 calls my SELECT statements works but then (during the same operations) Oracle returns an error Package or function %s is in an invalid state. Again I execute CREATE OR REPLACE FUNCTION raw_to_guid... in SqlDeveloper and everything is working fine for short time but after few minutes the same exception occurs.
It seems like Oracle automatically drops my user-defined function and I do not understand why because I have not any DROP FUNCTION statement in my code.
The same problem occurs when I close database session in my app and create it again.
Is there a way to add this function permamently?

Answer 1

It isn't dropped - you'd get a different error in that case. It is invalidated. Why? No idea.
Here's an example which shows what might have happened (only if your code looked like this):
Procedure (you don't have):
SQL> create or replace procedure p_test is
2 begin
3 null;
4 end;
5 /
Procedure created.
Procedure is called from the function (line #5):
SQL> create or replace function raw_to_guid( raw_guid in raw ) return varchar2
2 is
3 hex varchar2(32);
4 begin
5 p_test;
6 hex := rawtohex(raw_guid);
7
8 return substr(hex, 7, 2)
9 || substr(hex, 5, 2)
10 || substr(hex, 3, 2)
11 || substr(hex, 1, 2)
12 || '-'
13 || substr(hex, 11, 2)
14 || substr(hex, 9, 2)
15 || '-'
16 || substr(hex, 15, 2)
17 || substr(hex, 13, 2)
18 || '-'
19 || substr(hex, 17, 4)
20 || '-'
21 || substr(hex, 21, 12);
22
23 end;
24 /
Function created.
Does it work? Yes:
SQL> select raw_to_guid('abc') res from dual;
RES
----------
BC0A----
SQL>
But, if I drop the procedure, function - which references it - gets invalidated (error you got):
SQL> drop procedure p_test;
Procedure dropped.
SQL> select raw_to_guid('abc') res from dual;
select raw_to_guid('abc') res from dual
*
ERROR at line 1:
ORA-06575: Package or function RAW_TO_GUID is in an invalid state
SQL>
If I recreate the procedure, function recompiles automatically and everything is OK again:
SQL> create or replace procedure p_test is
2 begin
3 null;
4 end;
5 /
Procedure created.
SQL> select raw_to_guid('abc') res from dual;
RES
----------
BC0A----
SQL>
Code you posted (if that's the whole code) probably doesn't suffer from that; substr and rawtohex certainly aren't dropped or were somehow invalidated so that it would cause your function to also be invalidated (as a collateral victim).
What to do? When it fails again, don't just recreate it - check what's wrong by querying user_errors. For example:
SQL> drop procedure p_test;
Procedure dropped.
SQL> select raw_to_guid('abc') res from dual;
select raw_to_guid('abc') res from dual
*
ERROR at line 1:
ORA-06575: Package or function RAW_TO_GUID is in an invalid state
SQL> select line, position, text from user_errors where name = 'RAW_TO_GUID';
LINE POSITION TEXT
---------- ---------- --------------------------------------------------
5 3 PLS-00201: identifier 'P_TEST' must be declared
5 3 PL/SQL: Statement ignored
SQL>
Hopefully, you'll find the culprit.