I'm just saying that if you say developers shouldn't use listagg because there
was once a bug in it then you'd run out of features to use!
It would be better to use the test suite to say we can't use version 12.a.b.c
because our application uses listagg.
Sent from my Windows Phone
________________________________
From: Mark W. Farnham<mailto:mwf@xxxxxxxx>
Sent: 10/11/2016 10:23
To: dombrooks@xxxxxxxxxxx<mailto:dombrooks@xxxxxxxxxxx>;
woodwardinformatics@xxxxxxxxxxxxxxxx<mailto:woodwardinformatics@xxxxxxxxxxxxxxxx>;
'ORACLE-L'<mailto:oracle-l@xxxxxxxxxxxxx>
Subject: RE: Testing Oracle fitness for purpose/internal test suite
It can be useful to slap together examples of the code patterns in your
applications. Often, they can be described in the comments and reference the
documentation to do dual duty as “go-bys” for the cases where tracing through
sixty pages of documentation to assemble the almost bnf of Oracle’s manual
specification is better conveyed by simple examples to handle the simple cases.
But the main point is to constitute a regression test. Sometimes that means
some complicated code to show corner cases that had become buggy in some past
release. Complexities of code merges and backports sometimes cause temporarily
cured bugs to rise from the dead.
IF you build such a suite, commenting which chunks are intended as go-bys and
which are corner case demonstrations with a notation to NOT code like that is
useful.
Being able to run a suite of tests with a known output that can be diff-ed
versus the correct prior results is often a useful step that lets you know not
to bother with your code suite integration test. And you have a nice degenerate
case in hand to give along with your SR.
Of course such test suites can also be mis-used.
A test suite at a former client still includes (last I checked) a nice little
speed test for varrays for a specific purpose. For that purpose they were far
and away the easiest way to program. Unfortunately they were very slow. So the
code went into the regression test with a note to watch for the performance of
that use to improve so it could in the future be used to replace the complex
alternative code solution.
Your mileage may vary. I suppose a regression test suite might be somewhat
askew from a fitness for purpose test.
mwf
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On ;
Behalf Of Dominic Brooks
Sent: Thursday, November 10, 2016 4:40 AM
To: woodwardinformatics@xxxxxxxxxxxxxxxx; ORACLE-L
Subject: RE: Testing Oracle fitness for purpose/internal test suite
Interesting.
Trouble is that if you follow that thinking then for some of the bugs out
there, e.g wrong results not necessarily ORA-00600, you could come to the
conclusion that you shouldn't use SELECT at all!
Sent from my Windows Phone
________________________________
From: Michael D O'Shea/Woodward Informatics
Ltd<mailto:woodwardinformatics@xxxxxxxxxxxxxxxx>
Sent: 10/11/2016 08:53
To: ORACLE-L<mailto:oracle-l@xxxxxxxxxxxxx>
Subject: Testing Oracle fitness for purpose/internal test suite
Recently I encountered a very large organisation that had a comprehensive suite
of unit tests that tested stock "Oracle" SQL & PL/SQL behaviour. Yes I really
did write that. The client likely had a suite of unit tests that tested their
in-house developed code too but we were discussing testing of stock Oracle
functionality. In my book, I test my own code, and I expect the vendor to test
and certify their software is OK and "does what it says on the tin". I found
the client behaviour atypical to say the least. Their issue was that they had
commited to Oracle, but there was a quality confidence issue.
Their tests appeared to be done for two reasons.
1. To confirm Oracle patch/patch sets or version upgrades did not introduce
unexpected behaviour, or changes to existing RDBMS behaviour, that would
manifest itself in their critical business systems.
2. To lay the law down in terms of their internal coding standards, "though
shall not use LISTAGG" for example.
The following contrived and silly code snippet returns the length of a VARCHAR2
aggregated using LISTAGG. The LENGTH(y) is 4*999+3=3999. All good (again this
is contrived code, but from memory it is the type of scripted code the
organisation had in their test suite).
SQL>
SQL>
SQL> set serveroutput on size 100000
SQL> set timing on
SQL>
SQL> declare
2 xx char(999) := 'char not varchar2 so padded';
3 y varchar2(32767); --PL/SQL limit 32767, not 4000
4 begin
5 select distinct listagg(x4, ',')
6 within group (order by 1)
7 over (partition by 1)
8 into y
9 from (
10 select xx x4 from dual
11 union all select xx from dual
12 union all select xx from dual
13 union all select xx from dual
14 );
15 dbms_output.put_line(to_char(length(y)));
16 end;
17 /
3999
PL/SQL procedure successfully completed.
Elapsed: 00:00:00.02
SQL>
SQL>
SQL>
This is the expected behaviour, and 3999 the expected VARCHAR2 length (4 * 999
= 3996 + 3 for the 3 commas).
Something like the next test they performed is shown below. Although surprising
to me, it was the expected behaviour - the limit on LISTAGG is 4000 bytes not
32k, but it was a test "pass".
SQL>
SQL>
SQL>
SQL>
SQL> declare
2 xx char(1000) := 'char not varchar2 so padded';
3 y varchar2(32767); --PL/SQL limit 32767, not 4000
4 begin
5 select distinct listagg(x4, ',')
6 within group (order by 1)
7 over (partition by 1)
8 into y
9 from (
10 select xx x4 from dual
11 union all select xx from dual
12 union all select xx from dual
13 union all select xx from dual
14 );
15 dbms_output.put_line(to_char(length(y)));
16 end;
17 /
declare
*
ERROR at line 1:
ORA-01489: result of string concatenation is too long
ORA-06512: at line 5
Elapsed: 00:00:00.03
SQL>
The next test was a failure for the client and showcased their concerns.
SQL>
SQL>
SQL>
SQL>
SQL>
SQL> declare
2 xx char(2001) := 'char not varchar2 so padded';
3 y varchar2(32767); --PL/SQL limit 32767, not 4000
4 begin
5 select distinct listagg(x4, ',')
6 within group (order by 1)
7 over (partition by 1)
8 into y
9 from (
10 select xx x4 from dual
11 union all select xx from dual
12 union all select xx from dual
13 union all select xx from dual
14 );
15 dbms_output.put_line(to_char(length(y)));
16 end;
17 /
declare
*
ERROR at line 1:
ORA-00600: internal error code, arguments: [15851], [3], [2], [1], [1], [], [],
[], [], [], [], []
Elapsed: 00:00:00.08
SQL>
SQL>
While clearly this is just a plain old Oracle bug (an edge case - 2000 vs. 2001
bytes, half the 4000 byte limit), the test result confirmed the client
confidence issue in internal Oracle testing and fitness for purpose, with a
knock-on effect that their internal coding standards documentation prohibited
the use of LISTAGG (I do not know whether they raised the issue with Oracle but
this isn't my point), and other built-in functionality.
My question to you all is "Has anyone else encountered the behaviour where
clients run a suite of automated tests to test out-of-the-box Oracle stock
functionality, in otherwords running what are in effect unit tests that should
be performed by the Oracle prior to shipping, not the client?". Despite my
views of quality and testing at Oracle, I still cannot get my head around a
client testing out-of-the-box functionality with their own test suite like this.
I am not sure what version of Oracle the client was using, but I have just
retested using the following version (below) and can reproduce the behaviour.
Regards
Mike
http://www.strychnine.co.uk
SQL>
SQL>
SQL>
SQL> select * from v$version;
BANNER
CON_ID
--------------------------------------------------------------------------------
----------
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
0
PL/SQL Release 12.1.0.2.0 - Production
0
CORE 12.1.0.2.0 Production
0
TNS for Solaris: Version 12.1.0.2.0 - Production
0
NLSRTL Version 12.1.0.2.0 - Production
0
Elapsed: 00:00:00.02
SQL>
SQL>
SQL>
