Your multitenant container database (CDB) contains pluggable databases (PDBs), you are
connected to the HR_PDB. You execute the following command:
SQL > CREATE UNDO TABLESPACE undotb01
DATAFILE ‘u01/oracle/rddb1/undotbs01.dbf’ SIZE 60M AUTOEXTEND ON;
What is the result?
A.
It executes successfully and creates an UNDO tablespace in HR_PDB.
B.
It falls and reports an error because there can be only one undo tablespace in a CDB.
C.
It fails and reports an error because the CONTAINER=ALL clause is not specified in the
command.
D.
It fails and reports an error because the CONTAINER=CURRENT clause is not specified in the
command.
E.
It executes successfully but neither tablespace nor the data file is created.
Explanation:
Interesting behavior in 12.1.0.1 DB of creating an undo tablespace in a PDB. With
the new Multitenant architecture the undo tablespace resides at the CDB level and PDBs all share
the same UNDO tablespace.
When the current container is a PDB, an attempt to create an undo tablespace fails without
returning an error.
I just tested. It is strange that the create command is successful with a message “Tablespace created”. But when I run “select name from v$tablespace”, I don’t see the undo tablespace;
E is correct
E is correct
E – is true, trying to create undo at PDB statement, successed.
However setting undo_tablespace at using alter system command throws an error.
E as I found it in an Oracle University teaching documentation
E could be if it is sth like “segment creation deferred” … but
It would be nice if Max or the others share with us a piece of text as a proof or the name of the document so we can know what to search for this supposed new functionality of “reclaiming space on demand”
… I believe is E .. but I want to find the PROOF … help me
E
https://www.pythian.com/blog/undo-pdb-oracle-12c/
D this correct:
SQL> CREATE UNDO TABLESPACE undotb01 DATAFILE ‘/u01/app/oracle/db12cm/undotbs01.dbf’ SIZE 60M AUTOEXTEND ON;
Tablespace created.
SQL> select tablespace_name from dba_tablespaces;
TABLESPACE_NAME
——————————
SYSTEM
SYSAUX
TEMP
USERS
SQL> select name from dba_datafiles;
select name from dba_datafiles
*
ERROR at line 1:
ORA-00942: table or view does not exist
SQL> show parameter undo
NAME TYPE VALUE
———————————— ———– ——————————
temp_undo_enabled boolean FALSE
undo_management string AUTO
undo_retention integer 900
undo_tablespace string UNDOTBS1
SQL> !ls -lrth /u01/app/oracle/db12cm/undotbs01.dbf
ls: cannot access /u01/app/oracle/db12cm/undotbs01.dbf: No such file or directory
SQL>
Sorry, E
E