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Franck Pachot

Is CDB stable after one patchset and two PSU?

By Franck Pachot


There has been the announce that non-CDB is deprecated, and the reaction that CDB is not yet stable.

Well. Let’s talk about the major issue I’ve encountered. Multitenant is there for consolidation. What is the major requirement of consolidation? It’s availability. If you put all your databases into one server and managed by one instance, then you don’t expect a failure.

When 12c was out (and even earlier as we are beta testers) – – David Hueber has encountered an important issue. When a SYSTEM datafile was lost, then we cannot revocer it without stopping the whole CDB. That’s bad of course.

When Patchet 1 was out  (and we were beta tester again) I tried to check it that had been solved. I’ve seen that they had introduced the undocumented “_enable_pdb_close_abort” parameter in order to allow a shutdown abort of a PDB. But that was worse. When I dropped a SYSTEM datafile the whole CDB instance crashed immediately. I opened a SR and Bug 19001390 ‘PDB system tablespace media failure causes the whole CDB to crash’ was created for that. All is documented in that blog post.

Now the bug status is: fixed in (Oct 2014) Database Patch Set Update

Good. I’ve installed the latest PSU which is (Jan 2015) And I test the most basic recovery situation: loss of a non-system tablespace in one PDB.

Here it is:


RMAN> report schema;
Report of database schema for database with db_unique_name CDB

List of Permanent Datafiles
File Size(MB) Tablespace RB segs Datafile Name
—- ——– ——————– ——- ————————
1 800 SYSTEM YES /u02/oradata/CDB/system01.dbf
3 770 SYSAUX NO /u02/oradata/CDB/sysaux01.dbf
4 270 UNDOTBS1 YES /u02/oradata/CDB/undotbs01.dbf
5 250 PDB$SEED:SYSTEM NO /u02/oradata/CDB/pdbseed/system01.dbf
6 5 USERS NO /u02/oradata/CDB/users01.dbf
7 490 PDB$SEED:SYSAUX NO /u02/oradata/CDB/pdbseed/sysaux01.dbf
11 260 PDB2:SYSTEM NO /u02/oradata/CDB/PDB2/system01.dbf
12 520 PDB2:SYSAUX NO /u02/oradata/CDB/PDB2/sysaux01.dbf
13 5 PDB2:USERS NO /u02/oradata/CDB/PDB2/PDB2_users01.dbf
14 250 PDB1:SYSTEM NO /u02/oradata/CDB/PDB1/system01.dbf
15 520 PDB1:SYSAUX NO /u02/oradata/CDB/PDB1/sysaux01.dbf
16 5 PDB1:USERS NO /u02/oradata/CDB/PDB1/PDB1_users01.dbf

List of Temporary Files
File Size(MB) Tablespace Maxsize(MB) Tempfile Name
—- ——– ——————– ———– ——————–
1 60 TEMP 32767 /u02/oradata/CDB/temp01.dbf
2 20 PDB$SEED:TEMP 32767 /u02/oradata/CDB/pdbseed/pdbseed_temp012015-02-06_07-04-28-AM.dbf
3 20 PDB1:TEMP 32767 /u02/oradata/CDB/PDB1/temp012015-02-06_07-04-28-AM.dbf
4 20 PDB2:TEMP 32767 /u02/oradata/CDB/PDB2/temp012015-02-06_07-04-28-AM.dbf

RMAN> host “rm -f /u02/oradata/CDB/PDB1/PDB1_users01.dbf“;
host command complete

RMAN> alter system checkpoint;
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-00601: fatal error in recovery manager
RMAN-03004: fatal error during execution of command
ORA-01092: ORACLE instance terminated. Disconnection forced
RMAN-03002: failure of sql statement command at 02/19/2015 22:51:55
ORA-03113: end-of-file on communication channel
Process ID: 19135
Session ID: 357 Serial number: 41977
ORACLE error from target database:
ORA-03114: not connected to ORACLE


Ok, but I have the PSU:


$ /u01/app/oracle/product/12102EE/OPatch/opatch lspatches
19769480;Database Patch Set Update : (19769480)


Here is the alert.log:


Completed: alter database open
2015-02-19 22:51:46.460000 +01:00
Shared IO Pool defaulting to 20MB. Trying to get it from Buffer Cache for process 19116.
Dumping current patch information
Patch Id: 19769480
Patch Description: Database Patch Set Update : (19769480)
Patch Apply Time: 2015-02-19 22:14:05 GMT+01:00
Bugs Fixed: 14643995,16359751,16870214,17835294,18250893,18288842,18354830,
2015-02-19 22:51:51.113000 +01:00
db_recovery_file_dest_size of 4560 MB is 18.72% used. This is a
user-specified limit on the amount of space that will be used by this
database for recovery-related files, and does not reflect the amount of
space available in the underlying filesystem or ASM diskgroup.
Setting Resource Manager plan SCHEDULER[0x4446]:DEFAULT_MAINTENANCE_PLAN via scheduler window
Setting Resource Manager CDB plan DEFAULT_MAINTENANCE_PLAN via parameter
2015-02-19 22:51:54.892000 +01:00
Errors in file /u01/app/oracle/diag/rdbms/cdb/CDB/trace/CDB_ckpt_19102.trc:
ORA-63999: data file suffered media failure
ORA-01116: error in opening database file 16
ORA-01110: data file 16: ‘/u02/oradata/CDB/PDB1/PDB1_users01.dbf
ORA-27041: unable to open file
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
Errors in file /u01/app/oracle/diag/rdbms/cdb/CDB/trace/CDB_ckpt_19102.trc:
ORA-63999: data file suffered media failure
ORA-01116: error in opening database file 16
ORA-01110: data file 16: ‘/u02/oradata/CDB/PDB1/PDB1_users01.dbf’
ORA-27041: unable to open file
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
USER (ospid: 19102): terminating the instance due to error 63999
System state dump requested by (instance=1, osid=19102 (CKPT)), summary=[abnormal instance termination].
System State dumped to trace file /u01/app/oracle/diag/rdbms/cdb/CDB/trace/CDB_diag_19090_20150219225154.trc
ORA-1092 : opitsk aborting process
2015-02-19 22:52:00.067000 +01:00
Instance terminated by USER, pid = 19102


You can see the bug number in ‘bug fixed’ and the instance is still terminating after media failure on a PDB datafile. That’s bad news. 


I’ve lost one datafile. At first checkpoint the CDB is crashed. I’ll have to open an SR again. But for sure consolidation through multitenancy architecture is not yet for sensible production.


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Franck Pachot
Franck Pachot

Principal Consultant / Database Evangelist
Oracle ACE Director, Oracle Database OCM 12c
AWS Database Specialty certified, AWS Data Hero
Oak Table member

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