Oracle 1z0-888 Free Practice Questions

NEW QUESTION 1
Which two statements are true about InnoDB auto-increment locking?

• A. InnoDB never uses table_level locks.
• B. InnoDB always protects auto-increment updates with a table-level lock
• C. InnoDB does not use locks to enforce auto-increment uniqueness.
• D. The auto-increment lock can be a table-level lock.
• E. Some settings for innodb_autoinc_lock_mode can help reduce lockin

Answer: DE

NEW QUESTION 2
On a master server that is using statement-based replication, a table of log data has become very large. You decide to delete 100.000 rows.
Which two methods can be independently invoked to ensure that the delete is properly propagated to the slave? (Choose two.)

• A. Change the replication mode to mixed before issuing any delete statements when the limit clause is used.
• B. If the data modification is non-deterministic, the query optimizer will resolve any potential issues.
• C. Use the limit clause to limit the deletion to 100.000 rows.
• D. Use the limit clause in conjunction with the order 3Y claus

Answer: AD

NEW QUESTION 3
A simple master-to-slave replication is currently being used. This information is extracted from the SHOW SLAVE STATUS output:

You execute a ‘SHOW CREATE TABLE mytable” on the slave:

The table mytable on the slave contains:

You have issued a STOP SLAVE command. You have determined that it is safe to skip the transaction in this case. One or more statements are required before you can issue a START SLAVE command to resolve the duplicate key error. Which statement should be used?

• A. SET GTID_NEXT=”CONSISTENCY”; BEGIN; COMMIT;SET GTID_NEXT=”AUTOMATIC”;
• B. SET GTID_NEXT=”5da6b4f5-6f60-11e8-b2d6-0010e05f3e06:8”; BEGIN; COMMIT; SET GTID_NEXT=”AUTOMATIC”;
• C. SET GLOBAL SQL_SKIP_SLAVE_COUNTER=1
• D. SET GLOBAL enforce_gtid_consistency=ON
• E. SET GTID_EXECUTED=”5da6b4f5-6f60-11e8-b2d6-0010e05f3e06:8”;

Answer: C

NEW QUESTION 4
Group Replication uses global transaction identifiers to track executed transactions and are fundamental in avoiding transaction conflict. Which additional three steps help in avoiding conflicts in group replication?

• A. Set isolation level to be SERIALIZABLE.
• B. Use the binary log row format.
• C. Set isolation level to be READ COMMITTED.
• D. Configure IPv6 network for hosts.
• E. Guarantee a secondary index on every table.
• F. Guarantee a primary key on every table.
• G. Set multiple slave parallel worker thread

Answer: ABF

NEW QUESTION 5
Consider the key buffer in a MySQL server. Which two statements are true about this feature?

• A. It caches index blocks for MyISAM tables only.
• B. It caches index blocks for all storage engine tables.
• C. It is a global buffer.
• D. It is set on a per-connection basis.
• E. It caches index blocks for InnoDB tables onl

Answer: AD

NEW QUESTION 6
The /myfolder/my.cnf file has option set: [mysqld] skip-log-bin
/myfolder2/my.cnf has this option set: [mysqld] log-bin = /valid/path/to/mysqlbinlog
All mentioned paths are accessible to the account that you are currently using. Assume that any other options mentioned in either file are valid and legal option definitions.
You start an instance by using this command line:
mysqld --defaults-file=/myfolder/my.cnf --defaults-extra-file=/myfolder2/my.cnf What is the outcome?

• A. MySQL starts and Binary Logging is enabled.
• B. MySQL fails to start due to the conflicting options in the configuration files.
• C. MySQL fails to start due to conflicting options on the command line.
• D. MySQL starts but Binary Logging is disable

Answer: C

NEW QUESTION 7
A MySQL Server has been running an existing application successfully for six months. The my.cnf is adjusted to contain this additional configuration:

The MySQL Server is restarted without error.
What effect will the new configuration have on existing account?

• A. They are not affected by this configuration change.
• B. They all connect via the secure sha256_password algorithm without any configuration change.
• C. They will have their passwords updated on start-up to sha256_password format.
• D. They will have to change their password the next time they login to the serve

Answer: A

NEW QUESTION 8
Consider the join_buffer_size parameter in MySQL Server. Which two statements are true about the join buffer?

• A. The value should be increased if the client performs several SELECT operations.
• B. The join buffer is set per connection.
• C. The join buffer is used to process sorts when complex joins are being performed.
• D. The value should be increased from the default if the query joins large rows without using an index.
• E. The join buffer is global and can be changed only by restarting the serve

Answer: CD

NEW QUESTION 9
You have installed MySQL Server for the first time on your system. However, the data directory along with the tables in the mysql system database are missing. Which step do you perform to create the contents of the data directory?

• A. Run the create_system_tables.sql file
• B. Run the mysql_unpack.sql file
• C. Invoke mysqld with the --initialize option.
• D. Invoke mysql with the --initialize optio

Answer: C

NEW QUESTION 10
You have a MySQL instance with the following variables in the /etc/my.cnf file:

You issue these statements: USE prices;
UPDATE sales.january SET amount=amount+1000;
An hour after excluding the statements, you realize that you made a mistake and you want to go to the binary log and look at the statements again.
Which statement is true? (Choose two.)

• A. You would receive an error on the statement because you cannot update a different database that what is specified with the USE statement.
• B. The changes caused by the UPDATE statement are logged to the binary log because the instance is using --binlog-format = ROW
• C. The statement would fail because you cannot update more than one row at a time when using –binlogformat = ROW.
• D. Nothing is logged because you are executing an UPDATE statement that will cause changes to more than one row, and you do not have the --binlog-format value set to STATEMENT.
• E. Nothing was written to the binary log because you cannot perform a calculation in a query without enclosing the statement in single quotation marks.

Answer: DE

NEW QUESTION 11
Force Majeure is a catastrophic failure on a major level of the database operation. Regular backups are key to helping avoid data loss in such situations.
Which two other steps can help avoid data loss in a major catastrophe?

• A. Implement a failover strategy to another geographic location.
• B. Create a master-master pair for each service.
• C. Have a second data centre in a different region or country.
• D. Keep software updated to the latest version.
• E. Use RAID 10 storage for datA.
• F. Use on-site network-attached storage to separate service from dat

Answer: AC

NEW QUESTION 12
You have a consistent InnoDB backup created with mysqldump, the largest table is 50 GB in size. You start to restore your backup with this command;
shell> mysql –u root –p < backup.sql
After 30 minutes, you notice that the rate of restore seems to have slowed down. No other processes or external factors are affecting server performance.
Which is the most likely explanation for this slowdown?

• A. The MySQL server has stopped inserting data to check index consistency.
• B. InnoDB is doing CRC32 checks over the tablespace data as it grows.
• C. The MySQL server is taking a periodical snapshot of data so it can resume the restore if it is interrupted mid-way.
• D. InnoDB has filled the redo log and now must flush the pages.
• E. Secondary indexes no longer fit into the buffer poo

Answer: A

NEW QUESTION 13
Consider the index information for the dept_emp table in the employee’s schema:

Which two conclusions can be made based on the output of the query?

• A. There are three indexes on the table.
• B. There is a redundant index on the dept_no column.
• C. The secondary indexes are optimized for unique key look-ups.
• D. The values on the emp_no column must be unique.
• E. The selectivity of the dept_no column is the best of the indexed columns.
• F. There is a redundant index on the emp_no colum

Answer: CF

NEW QUESTION 14
You enable binary logging on MySQL Server with the configuration: binlog-format=STATEMENT log-bin
Which database updates are logged on the master server to the binary log by default?

• A. all updates except to the TEMPDB database
• B. all updates except to the PERFORMANCE_SCHEMA database
• C. all updates not involving temporary tables
• D. all updates to the default database, except temporary tables
• E. all updates to all databases

Answer: D

NEW QUESTION 15
When you examine a new MySQL installation with default configuration, you find a file called ibdata1 in the database directory. Which two statements are true about this file?

• A. it contains the binary log.
• B. it contains a general tablespace.
• C. it is the default location for all new tables that you create.
• D. it contains the system tablespace.
• E. it contains the redo log.
• F. it contains the undo lo

Answer: CD

NEW QUESTION 16
Suppose you are adding rows to a MyISAM table and the --datadir location runs out of disk space. What will happen when this occurs?

• A. The server will crash.
• B. The server suspends that INSERT operation until space becomes available.
• C. An error message will be returned to the client .Server Error: ER_IO
• D. The server suspends operations for all storage engines until space becomes availabl

Answer: B

NEW QUESTION 17
Is it true that binary backups always take less space than text backups?

• A. Yes, because binary backups only contain data, and not statements required to insert data into the tables.
• B. No, because text backups can have optimizations, which make them smaller, such as updating many rows at once.
• C. No, because if InnoDB tables contain many empty pages, they could take more space than the INSERT statements.
• D. Yes, because even if InnoDB tables contain many empty pages, text backups have empty INSERT statements for them.

Answer: C

NEW QUESTION 18
A MySQL server was initialized with separate UNDO tablespaces. Users complain that when they roll back large transactions, the time to process the request takes too long. The DBA would like to move the MySQL InnoDB UNDO tablespace to a solid-state drive (SSD) for better performance. Is this possible and how?

• A. Ye
• B. Shut down the mysqld process, enable the transportable_tablespace option, and move the UNDO directory to the SSD.
• C. Ye
• D. Shut down, copy the UNDO tablespaces to the new location, and change the innodb_undo_directory value in your my.cnf.
• E. N
• F. The UNDO tablespaces must remain on the same file system as the system tablespaces.
• G. N
• H. The sequential write pattern of the UNDO tablespaces is not supported on modern SSD block device

Answer: C

NEW QUESTION 19
Which two are considered good security practices when using passwords? (Choose two.)

• A. Use one-way encryption for storage of passwords.
• B. Store passwords external to the database.
• C. Choose short passwords to save on storage space.
• D. Use simple keyboard actions that give mixed letters.
• E. Do not use dictionary-based word

Answer: AE

NEW QUESTION 20
Which statement is true about using Microsoft Windows Cluster as a platform for MySQL?

• A. It relies on the shared disk architecture being visible to both servers.
• B. It is provided by means of IP-level disk replication.
• C. It implements High Availability by using the NET Connector's load balancing capabilities.
• D. It is a shared-nothing architectur

Answer: A

NEW QUESTION 21
MySQL is installed on a Linux server and has this configuration:
[mysqld] user=mysql
datadir=/data/mysql/
As the ‘root’ user, you change the datadir location by executing:
shell> cp –R /var/lib/mysql /data/mysql/ shell> chown –R mysql /data/mysql
What is the purpose of changing ownership of datadir to the ‘mysql’ user?

• A. MySQL needs to be run as the root user, but files cannot be owned by it.
• B. The mysqld process requires all permissions within datadir to be the same.
• C. MySQL cannot be run as the root user.
• D. MySQL requires correct file ownership while remaining secur

Answer: A

NEW QUESTION 22
What two statements are true regarding FLUSH TABLES FOR EXPORT?

• A. It can be used to export TEMPORARY tables.
• B. Table only exports when the table has its own tablespace.
• C. The InnoDB Storage engine must be used for the table being exported.
• D. It is the safest way to extract tables from the shared tablespace.
• E. Partitioned tables are not supporte

Answer: AB

NEW QUESTION 23
Consider that local disk files are accessible via MySQL with commands such as: mysql> LOAD DATA LOCAL INFILE ‘/etc/passwd’ INTO TABLE mypasswords; What change could be made to stop any breach via this insecurity?

• A. executing REVOKE LOADFROM *.*
• B. setting the --local-service=0 option when starting mysqld
• C. executing REVOKEFILEFROM *_*
• D. executing REVOKEFILE ON *_* FROM ‘ ‘@’%’
• E. setting the --local-infile=0 option when starting mysqld
• F. setting the --open-files-limit=0 option when starting mysqld

Answer: F

NEW QUESTION 24
You inherited a busy InnoDB OLTP Instance with 100 schemas and 100 active users per schema. Total dataset size is 200G with an average schema size G.
The data is transient and is not backed up and can be repopulated easily. Performance and responsiveness of the DB is paramount.
The query pattern for the DB instance is split 90/10 read/write. DB host is dedicated server with 256G RAM and 64 cores.
One of your colleagues made some recent changes to the system and users are now complaining of performance impacts. Which four configuration file edits might your colleague have performed to cause the negative DB performance?

• A. table_open_cache = 64
• B. innodb_buffer_pool_instances=64 innodb_buffer_pool_size=200G
• C. log_bin=mysql –bin Innodb_flush_log_at_trx_commit=1
• D. sync_binlog=10
• E. innodb_flush_method=O_DIRECT
• F. max_heap_table_size = 2G tmp_table_size=2G
• G. query_cache_size = 2G query_cache_enabled=1
• H. innodb_flush_log_at_trx_commit=0

Answer: ABEG

NEW QUESTION 25
A master-slave replication setup has the slave showing this error:

On the master server, the binary logs show:

What could explain this error? (Choose two.)

• A. binlog_cache_size=1024 is too small and transactions are lost.
• B. binlog_format=STATEMENT and a non-deterministic query was executed.
• C. enforce_gtid_consistency=ON and consistency is broken between the master and the slave.
• D. The sync_relay_log=1000 setting on the slave is too small.
• E. sync_binlog=0 and the master server crashe

Answer: AC

NEW QUESTION 26
......