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1Z0-060 · Question #113

Flashback is enabled for your multitenant container database (CDB), which contains two pluggable database (PDBs). A local user was accidently dropped from one of the PDBs. You want to flash back the…

The correct answer is D. 3 and 1. After FLASHBACK DATABASE the CDB must be opened with RESETLOGS to establish a new log incarnation before any PDB can be opened, so the required sequence is command 3 followed by command 1.

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Question

Flashback is enabled for your multitenant container database (CDB), which contains two pluggable database (PDBs). A local user was accidently dropped from one of the PDBs. You want to flash back the PDB to the time before the local user was dropped. You connect to the CDB and execute the following commands: SQL > SHUTDOWN IMMEDIATE SQL > STARTUP MOUNT SQL > FLASHBACK DATABASE to TIME "TO_DATE (08/20/12' , MM/DD/YY')"; Examine following commands: 1. ALTER PLUGGABLE DATABASE ALL OPEN; 2. ALTER DATABASE OPEN; 3. ALTER DATABASE OPEN RESETLOGS; Which command or commands should you execute next to allow updates to the flashback back schema?

Options

  • AOnly 1
  • BOnly 2
  • COnly 3
  • D3 and 1
  • E1 and 2

How the community answered

(27 responses)
  • A
    4% (1)
  • B
    30% (8)
  • C
    11% (3)
  • D
    48% (13)
  • E
    7% (2)

Why each option

After FLASHBACK DATABASE the CDB must be opened with RESETLOGS to establish a new log incarnation before any PDB can be opened, so the required sequence is command 3 followed by command 1.

AOnly 1

ALTER PLUGGABLE DATABASE ALL OPEN cannot be executed while the CDB is still in MOUNT state after flashback; the CDB root must be opened with RESETLOGS first or Oracle will return an error because the PDB files are still in a pre-open incarnation.

BOnly 2

ALTER DATABASE OPEN without the RESETLOGS clause will fail after FLASHBACK DATABASE because the SCN has been wound back, creating a gap in the redo stream that Oracle refuses to bridge without establishing a new log incarnation via RESETLOGS.

COnly 3

Executing only command 3 (ALTER DATABASE OPEN RESETLOGS) opens the CDB root but leaves all PDBs in MOUNTED state; users cannot connect to the PDB or perform the schema updates needed to confirm recovery until the PDBs are explicitly opened with command 1.

D3 and 1Correct

FLASHBACK DATABASE rolls back the redo log timeline, which requires ALTER DATABASE OPEN RESETLOGS (command 3) to create a new database incarnation and bring the CDB root out of MOUNT state. Only after the CDB root is open can ALTER PLUGGABLE DATABASE ALL OPEN (command 1) be issued to bring the PDBs online and permit DML against the recovered schema.

E1 and 2

Commands 1 and 2 together are incorrect because ALTER DATABASE OPEN (command 2) fails post-flashback without RESETLOGS, and attempting to open PDBs before a valid RESETLOGS open would reference an invalid incarnation and risk data corruption.

Concept tested: CDB flashback database recovery and RESETLOGS with PDB open sequence

Source: https://docs.oracle.com/en/database/oracle/oracle-database/19/multi/using-oracle-flashback-technology-with-cdbs-and-pdbs.html

Topics

#CDB flashback#PDB recovery#RESETLOGS#flashback database

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