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Thursday, October 20, 2011



Oracle OCP test Quiz


 
Question:
1. Which of the following events would not be a good candidate for a pager alert?
A. Tablespace is growing beyond 95% full.
B. Buffer hit ratio is at 65%
C. A table has reached maximum extents.
D. The redo log file system is at 95% full.

Correct Answer:
The correct answer is B. Buffer hit ratio is at 65%.


Explanation:
The correct answer is B. Buffer hit ratio is at 65%. This is because the remedy is increasing db_block_buffers, and this cannot be done without stopping and re-starting the database.  Which of the following events would not be a good candidate for a pager alert?  A, C, and D are incorrect because these are excellent opportunities to fix a looming problem before the database experiences a problem.


Question:
2. Which of the following is not a function of the event manager window of the OEM console?
A. Defining events and thresholds.
B. Defining corrective actions for alerts.
C.  Associating events with remote databases.
D. defining a new index for a table.

Correct Answer:
D. defining a new index for a table.

Explanation:
The correct answer is D. Defining a new index for a table. Which of the following is not a function of the event manager window of the OEM console?  A is incorrect because event definition is a major function of the event manager.  B is incorrect because corrective actions are an option within the event manager.  C is incorrect because


Question:
3. Which statement is false about the intelligent agent?
A. You must define one agent for each remote database on your server.
B. The agent runs as an independent server process on each remote node.
C. The agent can be used to facilitate job scheduling through the OEM console job schedule window.
D. The agent uses the SNMP protocol to communicate with the OEM console.

Correct Answer:
A. You must define one agent for each remote database on your server.

Explanation:
The correct answer is A. You must define one agent for each remote database on your server. Which statement is false about the intelligent agent?  B is incorrect because the agent is indeed an independent server process. C is incorrect because agents are used for job scheduling.  D is incorrect because agents use SNMP to communicate with the OEM console.


Question:
4. Prior to the OEM console, the Remote DBAs continued to perform the OEM functions.  Which tool is not an alternative to OEM functionality?
A. Using the UNIX crontab to schedule database maintenance
B. Using Unix mail to send the Remote DBA alerts about database problems
C. Using Schema manager to display the database tables names.
D. Using SQL*Plus to start and stop the database.

Correct Answer:
D. Using SQL*Plus to start and stop the database.

Explanation:
The correct answer is D, Using SQL*Plus to start and stop the database.  This is because SQL*Plus cannot issue “startup” or “shutdown” commands. Prior to the OEM console, the Remote DBA’s continued to perform the OEM functions.  Which tool is not an alternative to OEM functionality? A is incorrect because the Unix crontab is a very good non-centralized job scheduler for Oracle.  B is incorrect because Unix mail has been used for year to send alerts to Remote DBA’s.  C is incorrect because the Schema Manager is almost identical in functionality to the OEM navigator window. 


Question:
5. Which is not a function available from the OEM console?
A. Maintaining the Oracle*Net topology
B.  Displaying the indexes for a table
C. Displaying a list of databases
D. Displaying a list of all maintenance tasks.

Correct Answer:
A. Maintaining the Oracle*Net topology

Explanation:
The correct answer is A, maintaining the Oracle*Net topology.  This is because the Oracle*Net assistant the Oracle*Net Easy are used for these tasks. Which is not a function available from the OEM console? B is incorrect because indexes can be displayed from the navigator.  C is incorrect because a list of database is available from the navigator.  D is incorrect because lists of maintenance tasks can be displayed in the job scheduler.



Question:
6.  Which is false about the ops$ Oracle user?
A. ops$ allows Oracle users to connect from PC clients without supplying a password.
B. ops$ was used before Oracle supported the “identified externally” clause.
C. ops$ allows OS authentication from any UNIX Oracle*Net client.
D. ops$ requires that the os_authent_prefix be set in the init.ora.

Correct Answer:
A. ops$ allows Oracle users to connect from PC clients without supplying a password.

Explanation:
The correct answer is A. ops$ allows Oracle users to connect from PC clients without supplying a password. Which is false about the ops$ Oracle user?  B is incorrect because ops$ did precede external identification.  C is incorrect because ops$ does allow OS authentication from UNIX, just like external identification.  D is incorrect because the os_authent_prefix must be set to ops$.


Question:
7. How would you define an Oracle user who wants OS authentication on the server, but wants also to connect from a PC client?
A.  create user fred identified externally;
B. create use fred identified by ops$.
C create user ops$fred identified externally.
D. create user ops$fred identified by fredpass;

Correct Answer:
D. create user ops$fred identified by fredpass;

Explanation:
The correct answer is D. create user ops$fred identified by fredpass;. How would you define an Oracle user who wants OS authentication on the server, but wants also to connect from a PC client? A and C are incorrect because all Oracle*Net PC clients cannot allow connections from externally identified users.  B is incorrect because it is silly.


Question:
8.  If you want to completely disable OS password authentication, which init.ora parameters values would you choose?
A. os_authent_prefix=””
B. remote_os_authent=false
C. remote_os_authent=true
D. os_authent_prefix=”ops$”

Correct Answer:
B. remote_os_authent=false

Explanation:
The correct answer is B. remote_os_authent=false. If you want to completely disable OS password authentication, which init.ora parameters values would you choose?  A and D are incorrect because os_authent_prefix does not control external access.  C is incorrect because a value of “true” will enable access, not disable it.


Question:
9. Which is false about the IDENTIFIED EXTERNALLY clause?
A.  Remote users that have external identification will be able to connect to the local database regardless of any init.ora settings.
B. UNIX users with external identification may connect to SQL*Plus without either a user ID or a password.
C. External users are not allowed to have an Oracle password, and cannot connect via PC GUI tools such as Oracle*Net Assistant.
D. External users have fewer passwords to remember.

Correct Answer:
A.  Remote users that have external identification will be able to connect to the local database regardless of any local init.ora settings.

Explanation:
The correct answer is A.  Remote users that have external identification will be able to connect to the local database regardless of any local init.ora settings. Which is false about the IDENTIFIED EXTERNALLY clause?  B is incorrect because external ID’s are gathered from UNIX.  C is incorrect because external users cannot use Oracle*Net assistant.  D is incorrect because it is true that externally identified user have less passwords to remember.


Question:
10.  Which is not a feature of the Advanced Networking Option?
A. The use of third-party security tools such as Kerberos.
B. The use of data encryption.
C. The remote validation of Oracle*Net user password.
D. The use of single user sign-on. 

Correct Answer:
C. The remote validation of Oracle*Net user password.

Explanation:
The correct answer is C. The remote validation of Oracle*Net user password. Which is not a feature of the Advanced Networking Option?  A is incorrect because third-party tools are used for encryption.  B is incorrect because data encryption is the most important feature of the advanced networking option.  D is incorrect because advanced networking can enforce single sign-on.


Question:
11. Which Oracle*Net parameter file would not contain information for the Advanced Networking Option?
A. init.ora
B. listener.ora
C. sqlnet.ora
D. tnsnames.ora

Correct Answer:
D. tnsnames.ora

Explanation:
The correct answer id D. tnsnames.ora. Which Oracle*Net parameter file would not contain information for the Advanced Networking Option?  A is incorrect because the init.ora parameter remote_os_authent must be set to false.  B is incorrect because the listener.ora needs SQLNET.AUTHENTICATION_SERVICES=(NONE).  C is incorrect because the SQLNET.AUTHENTICATION_SERVICES parameter must be set.


Question:
12.  Which is not a possible security exposure within Oracle*Net?1
A. Public database links.
B. Granting access on remote tables to “public”.
C. Using the ops$ user prefix.
D. Connecting to SQL*Plus with your user ID and password on the command line.

Correct Answer:
C. Using the ops$ user prefix.

Explanation:
The correct answer is C. Using the ops$ user prefix. Which is not a possible security exposure within Oracle*Net?  A is incorrect because public database links can use used by anyone who knows the link name.  B is incorrect because public tables can be viewed by all database links.  D is incorrect because ops$ users can be supplied with a password.


Question:
13. Which is not a reason why Oracle requires a password for remote PC-based Oracle*Net clients, but not for UNIX-based Oracle*Net clients?
A. Because there are not user ID’s within Windows 98 clients.
B. Because PC’s are subject to hacking by unauthorized users.
C. Because Windows NT allows the administrator to create “imposters” to connect to Oracle.
D. Because ops$ prefixes are not supported by any of the Oracle PC GUI tools.

Correct Answer:
D. Because ops$ prefixes are not supported by any of the Oracle PC GUI tools.

Explanation:
The correct answer is D. Because ops$ prefixes are not supported by any of the Oracle PC GUI tools. Which is not a reason why Oracle requires a password for remote PC-based Oracle*Net clients, but not for UNIX-based Oracle*Net clients?  A is incorrect because it is true that Windows 98 does not have USER ID’s, and hence no OS level authentication.  B is incorrect because PC’s can easily be “hacked”.  C is incorrect because Windows NT administrators could gain access to an entire enterprise if they created “imposter” Oracle ID’s.



Question:
14. Which is not an advantage of an externally identified user?
A. Fewer Oracle passwords to remember.
B. Password checking by both the OS and by Oracle.
C. Better management of password security
D. No requirement to specify either the Oracle ID or the password.

Correct Answer:
B. Password checking by both the OS and by Oracle.

Explanation:
The correct answer is B. Password checking by both the OS and by Oracle. Which is not an advantage of an externally identified user?  A is incorrect because external identification does mean that there will be fewer passwords since they only exist within UNIX.  C is incorrect because UNIX will manage all passwords, and they will not be duplicated within Oracle.  D is incorrect because an externally identified does not have to specify either their user ID or a password when entering an Oracle utility such as SQL*Plus.



ORA-19809: limit exceeded for recovery files – db_recovery_file_dest_size and archiver error
As we  working on development systems  normal work around was to free up some space in the db_recovery_file_dest and hope that
that the database would continue after the archiver logger error.
Invariably we needed to restart the database and hope that the problem resolves itself.

The alert log typically shows an entry as follows :-
ORA-19815: WARNING: db_recovery_file_dest_size of 42949672960 bytes is 100.00% used, and has 0 remaining bytes available.
************************************************************************
You have following choices to free up space from flash recovery area:
1. Consider changing RMAN RETENTION POLICY. If you are using Data Guard,
then consider changing RMAN ARCHIVELOG DELETION POLICY.
2. Back up files to tertiary device such as tape using RMAN
BACKUP RECOVERY AREA command.
3. Add disk space and increase db_recovery_file_dest_size parameter to
reflect the new space.
4. Delete unnecessary files using RMAN DELETE command. If an operating
system command was used to delete files, then use RMAN CROSSCHECK and
DELETE EXPIRED commands.
************************************************************************
Errors in file /u00/app/oracle/diag/rdbms/sid/SID/trace/SID_ora_20214.trc:
ORA-19809: limit exceeded for recovery files
ORA-19804: cannot reclaim 1063256064 bytes disk space from 42949672960 limit
ARCH: Error 19809 Creating archive log file to ‘+FRA’

connect from Rman

RMAN > CHANGE ARCHIVELOG ALL VALIDATE;
RMAN > DELETE EXPIRED ARCHIVELOG ALL;
Metalink Document https://metalink.oracle.com/metalink/plsql/f?p=200:27:9917209390401703684::::p27_id,p27_show_header,p27_show_help:621248.995,1,1 has an unpublished note on the subject
Cause
~~~~~~~
We register all the information about what we place in the flash recovery area in
the rman repository/controlfile. If we determine that there is not sufficient space
in the recovery file destination, as set by dest_size then we will fail.
Just deleting the old backups/archive logs from disk is not sufficient as it’s the rman repository/controlfile
that holds the space used information.
Fix
~~~~
There are a couple of possible options.
1) Increase the parameter db_recovery_file_dest_size
2) Stop using the db_recovery_file_dest by unsetting the parameter.
( This assumes you never really wanted to use this option )
3) Remove the Entries from the rman repository/Controlfile
The removal is desribed in the RMAN documentation but this is a quick and
dirty way if you don’t have an rman repository – but could endanger your ability
to recover – so be careful.
a) delete unwanted archive log files from disk ( rm /del )
b) connect to rman
c) rman crosscheck archivelog all – marks the controlfile that the archives have been deleted
d) rman delete expired archivelog all – deletes the log entries identified above.