sid and pluggable

I wrote about SID there. (CONNECT_DATA=(SID=DB01)) is undocumented since Oracle 11gR1 and breaks things with multi-tenant / single-tenant.

You create a container CDB01 and a pluggable DB01, you can connect with

sqlplus "scott/tiger@

But one of your application has hardcoded SID=DB01

sqlplus "scott/tiger@
ORA-12514: TNS:listener does not currently know of 
    service requested in connect descriptor

How do you do the trick?

  • Remove the domain name in the pluggable
    alter session set container=DB01;
    alter system set db_domain='' 

  • You use the listener parameter USE_SID_AS_SERVICE
  • listener.ora


    You restart the listener and the database.

    sqlplus "scott/tiger@
    Connected to:
    Oracle Database 12c Enterprise Edition Release

    You just connected with SID to a pluggable database

Single-Tenant over bequeath connections

If you follow Oracle recommendation to use SingleTenant CDB instead of Non-CDB, then a lot of things will break.

I won’t go into details, but basically, in this new architecture, you have one core container, called CDB$ROOT, which is the default container where you connect to if you connect locally

sqlplus / as sysdba
SQL> select cdb from v$database;
SQL> select sys_context('USERENV','CON_NAME') from dual;

SQL> select con_id, NAME from V$CONTAINERS

---------- ----------
         1 CDB$ROOT
         2 PDB$SEED
         3 ST01

Then you’ll soon realise, you can no longer do what you used to do

SQL> create user u identified by u;
create user u identified by u
ERROR at line 1:
ORA-65096: invalid common user or role name

Some scripts still run in the root container. SHUTDOWN ABORT, ALTER SYSTEM SWITCH LOGFILE. Doing a full backup or clone probably won’t hurt you much. Relatively..

But now let’s imagine I have a very simple and very old script to lock scott
  echo "alter user scott account lock;"|
    sqlplus -s / as sysdba

This won’t work. I need to lock scott in the SingleTenant container ST01.

I could do this in the container

SQL> alter session set container=ST01;
  Session altered.
SQL> alter user scott account lock;
  User altered.

So fine, so good. NOW : how do I make this work without changing the script ?

Remember, non-cdb database, as they were used in Oracle 11, 10, 9, 8, 7 … are now deprecated. Remember, cdb is recommended. Now face it : it’ll break your dba scripts.

As a production dba, I don’t want to rewrite all the existing scripts. Some are ultra-old and used by people who did not write them.

One method for my script would be to change the container in a login script.

echo "alter session set container=ST01;" > /tmp/login.sql
export ORACLE_PATH=/tmp
  Session altered.
  User altered.  

(ORACLE_PATH in latest 12.1 and in 12.2, SQL_PATH in older release)

However, if my script must work with both CDB and non-CDB, I need to set the container in only this case.

In my login.sql, I first tried to implement some plsql logic, but alter session set container is not working (aka working with limitation) with execute immediate.

As well, I don’t want my script to break Oracle 11.

So I decide to do some sqlplus magic with defined variable.

set ver off feed off
-- 1) check if the column v$database.cdb exists
col column_name new_v cdb nopri
def cdb=null
select column_name from dba_tab_columns 
where owner='SYS' and 
table_name='V_$DATABASE' and column_name='CDB';
-- 2) if cdb is YES, then select a dynamic statement using V$PDB 
col pdb new_v pdb nopri
def pdb="null stmt from dual where 1=0"
'''set container="''||name||''"'' stmt from v$pdbs where name!=''PDB$SEED'''
from v$database 
where &cdb='YES';
-- 3) get a dynamic alter session statement. I use a dummy flagger for non-cdb
col stmt new_val stmt nopri
def stmt="SET FLAGGER=OFF"
select &pdb;
-- 4) alter session
alter session &stmt;
set feed 6
col column_name clear
col stmt clear
col pdb clear
undef cdb
undef stmt
undef pdb

Now I run my script

11g: ./
User altered.

12c-non-cdb: ./
User altered.

12cR2-single-tenant: ./
User altered.

DISCLAIMER: you shouldn’t use a global login.sql and you should know that secretly fixing old scripts may have side effects. Test, test and retest your code
DISCLAIMER 2: my frequent readers surely wonder if this statement generating a statement generating a statement is for an obfuscation contest

Legacy users get ORA-01017 in 12.2

The default case insensitive string disappeared in 12cR2, let’s call it the 10G string in this post, but it was the same since Oracle 7 at least. It was introduced in V5 or V6 to replace clear-text passwords.

What’s happening then with my ultra-old-accounts?

You could well set a new password (or the same password again) to each account to be migrated in 11g/12cR1 before moving to 12cR2.

If nobody knows the password and nobody can change it because it is hardcoded in the application and neither easy to read (hidden / obfuscated /encrypted) nor to change, then, you are in TROUBLE ! This is documented in Note 2075401.1

First disclaimer : it is a good thing to achieve a better security. SHA1 and SHA2 are a lot better than the oldstyle-longly-hacked-unsalted-case-insensitive-homemade-algorythm. SHA3 has been published in 2015 and it not used in Oracle 12cR2 yet. SHA2 is a bit older (2001) but still recommended. SHA1 is oldish (1995) and no-longer-recommended, collision has been detected. Read more on wikipedia or crypto101

SHA-1 was a really huge improvement when introduced in 11gR1. The old self-made algorythm has been a torture for Oracle Security team. It has been published on Internet. Extremly powerfull password cracker can find your “not-too-long” password in notime. In 11g, Oracle removed the 10g String from the DBA_USERS view. I wrote about this here. It remained on the base table, USER$ until 12cR2. Now Oracle completly removed it by default in 12cR2. 10 years after SHA1 was introduced in 11gR1.

Still. You are the dba. You want to migrate your database not to chase passwords.

You could edit your sqlnet.ora to allow 10g strings.


This works

SQL> sho parameter sec_case_sensitive_logon
NAME                      VALUE
------------------------- -----
sec_case_sensitive_logon  FALSE

     VALUES 'DC6F2B33D359A95B';
User created.
SQL> grant create session to u;
Grant succeeded.
SQL> conn u/abcdefg@pdb01
SQL> conn u/AbCdEfG@pdb01

If you have SQLNET.ALLOWED_LOGON_VERSION_SERVER=11, then you could keep the same setting of sec_case_sensitive_logon as in 11g. I recommmend the default (true).

But, that’s it ? Wellllllll… not sure.

In 12.1

SQL> select dbms_metadata.get_ddl('USER','U') from dual
     VALUES 'DC6F2B33D359A95B'

Let’s try in 12.2

SQL> select dbms_metadata.get_ddl('USER','U') from dual

While this is a perfectly working syntax, and IDENTIFIED BY VALUES is not supported *. So if create that user, then, obviously, the 10G string is lost.

Well, unsupported feature then? Hmm, yes. You should never have used identified by values.

Ok, so if I refresh my Test database with Production data, how can I save test passwords? You can’t. At least not in a supported way by using identified by values.

You could something like :

SQL> select 'alter user "'||name||
       '" identified by values '''||
       password||''';' txt
     from user$, v$instance 
     where version > '12.2' 
     and spare4 is null  
     and type# = 1
     and regexp_like(PASSWORD,'[A-F0-9]{16}');

alter user "U" identified by values

This may work. In Maybe not in 13. Maybe not in July. It’s not supported. If it does not work, it is NOT-A-BUG.

The SHA1 was introduced 10 years ago in Oracle 11gR1. If you have not changed your password in ten years, and you don’t know how many employees and ex-employees know this password, and it is case-insensitive, and its “pseudo-hashing-algorythm” has been hacked for maybe two decades, yet, I can only warmly recommend to change those accounts passwords !

Again: so if I refresh my Test database with Production data, how can I save test passwords ?
If I were you I would design a better system for login. For human users, use global users and an Identity solution, like Oracle Universal directory. For technical account, build yourself a tool that generate a random password, and update the user and credentials, something like

) ,'[^!#-~]'
) PW
from dual;

And use it to reset your technical user and to configure your application credentials.

* Note 554605.1: the 'IDENTIFIED BY VALUES' clause on a CREATE/ALTER USER statement is not officially documented, and is intended purely for internal

Monitor audit_file_dest !

Until 11.2, audit_file_dest used to remain small with default settings and reasonably sized and active database. Suddenly, in 12c, you will sooned or later get ORA-09925: Unable to create audit trail file.

At that point, no more connection is possible to the database, it is a complete loss of service.

Why suddenly in 12c ? This is because the default for audit_sys_operations changed to true. In 11g, you used to get an 1K file each time you connect as sysdba. So a few tousands sysdba connections a weeks, a few mega, no worries.

Mon Mar 27 14:08:01 2017 +02:00
LENGTH : '155'
CLIENT USER:[6] 'oracle'
STATUS:[1] '0'

Suddenly in 12c, you get plenty files that are many Mb. For instance for AUTOTASK jobs, every single select is dumped to the filesystem. A single week-end of an quiet database may generate 1Gb of *.aud files of DBMS_SCHEDULER.

Those DB001_j000_12345_20170327140802123456789.aud files are highly useless and annoying.

LENGTH : '641'
ACTION :[490] 'select /*+  no_parallel(t) no_parallel_index(t) dbms_stats cursor_sharing_exact use_weak_name_resl dynamic_sampling(0) no_monitoring xmlindex_sel_idx_tbl no_substrb_pad  */ substrb(dump("PERIOD_END_TIME",16,0
,64),1,240) val,
                      rowidtochar(rowid) rwid from "SYS"."WRP$_REPORTS_TIME_BANDS" t where rowid in (chartorowid('AABJ58AADAAAMsrAAA'),chartorowid('AABJ58AADAAAMsrAAB'),chartorowid('AABJ58AADAAAMsrAAC'),chartorowid('AABJ58A
STATUS:[1] '0'

Once your audit_file_dest is getting full, your database stops, so better delete those *_j00*_* and *_m00*_* quickly enough!

Restricted sqlplus and sql_script

Yesterday I wrote about execute sql script from plsql. Connor then posted a 12c new feature that I overviewed

If you are still considering the 11g approach with sqlplus, you should read about restricted sqlplus

If you run

sqlplus -L -s -R 3 scott/tiger@db01

lot’s of OS-command are disabled

SQL> get /etc/passwd
SP2-0738: Restricted command "get" not available
SQL> spool /etc/oratab
SP2-0738: Restricted command "spool" not available
SQL> host reboot
SP2-0738: Restricted command "host" not available

There is also a Product User Profile. I never saw any customer using this. I doubt it is very safe.

You could disable some commands

SQL> insert into system.PRODUCT_USER_PROFILE

Which prevents SCOTT from doing rollabck

SQL> rollback;
SP2-0544: Command "rollback" disabled in Product User Profile

but it doesn’t resist Rock & Roll

SQL> roll & rock
Rollback complete.

If you have 12c, go have a look at the doc for SQL_SCRIPT jobs

ANNOUNCEMENT: 12cR2 documentation is available

The doc is available. Check new features and stay tuned.

Okay, just 12 for today : HIGH compressed index, case insensitive database with bound collation, partitioned external tables, AL32UTF8 default for new database, listagg overflow, VALIDATE_CONVERSION, approx_percentile, json_exists, flashback pluggable database, the SHARING clause, RAC streched clusters site definition and INACTIVE_ACCOUNT_TIME in profile.

Some I like more than others 🙂

Okay, one more : SQLPLUS HISTORY !

To shrink or to move

If you delete most of the rows in one table, you probably want to regain that space, to minimize IO and fragmentation.

If you delete most of the rows in most of the tables, you probably also want to resize the datafile to reduce storage and backup space.

In this case, you could move your data in a new tablespace

alter table t move tablespace newts;

I wrote about this here : 2006/08/tablespace-maintenance-tasks.html

There is also an option to SHRINK. In oldish (pre-12cR2) releases, this had the advantage of being an online operation. In 12.2, include the online keyword.

SHRINK requires ROW MOVEMENT. I don’t like the idea of having the rowid’s changing. You have also a bunch of restrictions, amoung others on materialized view fast refreshes and index organized tables.

I am impatient to get this 12cR2. According to the doc, during an alter table move, transactions run uninterrupted on the table

OTN Appreciation Day : Partition your table online !

#ThanksOTN @oraclebase

No, I am not talking about DBMS_REDEFINITION, where you get a kind of online feeling.

No, I don’t want to rename my table, rename my foreign keys, my primary key, my not-null-constraints, recreate my referential integrity, recompile my triggers.

I just want to partition a non-partitioned table.


This is going to save me a lot of Saturday work 🙂

You need 12.2 to run this.

to R1 or to R2

In the past, most of my customers skipped R1 releases. That is, 8.1.7 -> 9.2 -> 10.2 -> 11.2. SAP does the same. For the very first time SAP plans to go to + some PSU in spring 2015. But only to avoid running out of support and without any fancy feature like Multitenant or in Memory., which is not available on AIX yet, will be the last patchset of 12cR1. It is the first and only patchset for that release. It is actually more than a patchset, as it introduced in memory database and JSON in the database.

The next release is expected beginning of 2016 on Linux. patching ends January 2018.

Should I I go to an already aborted release or should I buy extended support for until 2018 ?

Probably I will go both ways, depending on the applications.

Oracle on Windows

@mkratoch is speaking at 10am UGF2633: Managing Oracle 12c on Windows

Again, 12cR1ps1 came before AIX and HPUX.

SQL> select dbms_utility.port_string, version 
  from v$instance;

PORT_STRING          VERSION         
-------------------- -----------------