Warning: PDB altered with errors- opening PDB in Oracle 12.1

I was facing below error while opening pluggable database created on 12.1.0.2 using SEED PDB

SQL> show pdbs

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED

---------- ------------------------------ ---------- ----------

         2 PDB$SEED                       READ ONLY  NO

         3 PDB_1                          READ WRITE NO

         4 PDB_TECHON                     MOUNTED

SQL>

SQL> alter pluggable database PDB_TECHON open;

Warning: PDB altered with errors.

I have been cheeking alert log for the errors but could not find anything related to this particular warning. after searching on Oracle Metalink, I could figure out this bug in 12.1.0.2
We can check the message related to warning in pdb_plug_in_violations

SQL> select message,time from pdb_plug_in_violations;

MESSAGE                                                                                              TIME

---------------------------------------------------------------------------------------------------- ---------------------------------------------------------------------------

Sync PDB failed with ORA-959 during 'CREATE USER "C##dev_owner"  PROFILE "DEFAULT"                      14-DEC-18 02.42.18.368009 AM

    IDENTIFIED BY *DEFAULT TABLESPACE "USERS" CONTAINER=ALL

    TEMPORARY TABLESPACE "TEMP"

    ACCOUNT UNLOCK'

Basically it checks the default tablespace of comman users in every PDB created and throws warning if not able find the same, so the solution is to create USERS tablesapce in newly created PDB (PDB_TECHON).

Below we have switched to container PDB_TECHON and created USERS tablespace and restarted the pluggable database by connecting root container (CDB$ROOT), we can see PDB is opened with any warning this time.

SQL> alter session set container=PDB_TECHON;

Session altered.

SQL> show con_name

CON_NAME

------------------------------

PDB_TECHON

SQL>

SQL> create tablespace users datafile '+DATA01' size 100m;

Tablespace created.

SQL>  show pdbs

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED

---------- ------------------------------ ---------- ----------

         4 PDB_TECHON                     READ WRITE YES

SQL>

SQL>  alter session set container=CDB$ROOT;

Session altered.

SQL>  show pdbs

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED

---------- ------------------------------ ---------- ----------

         2 PDB$SEED                       READ ONLY  NO

         3 PDB_1                          READ WRITE NO

         4 PDB_TECHON                     READ WRITE YES

SQL>

SQL> alter pluggable database PDB_TECHON close;

Pluggable database altered.

SQL> show pdbs

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED

---------- ------------------------------ ---------- ----------

         2 PDB$SEED                       READ ONLY  NO

         3 PDB_1                          READ WRITE NO

         4 PDB_TECHON                     MOUNTED

SQL>

SQL> alter pluggable database PDB_TECHON open;

Pluggable database altered.

SQL> show pdbs

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED

---------- ------------------------------ ---------- ----------

         2 PDB$SEED                       READ ONLY  NO

         3 PDB_1                          READ WRITE NO

         4 PDB_TECHON                     READ WRITE NO

SQL> 

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