【dbdao.com 认证专题】- MySQL 5.6 - OCP考题讲解

A simple master-to-slave replication is currently being used. The following information is extracted from the SHOW SLAVE STATUS output:
Last_SQL_Error: Error 'Duplicate entry '8' for key 'PRIMARY'' on query. Default database: 'mydb'.
Query: 'insert into mytable VALUES ('8', 'George')'
Skip_Counter: 0
Retrieved_Gtid_Set: 38f32e23480a7-32a1-c323f78067fd37821: 1-8
Auto_Position: 1
You execute a "SHOW CREATE TABLE mytable" on the slave:
CREATE TABLE 'mytable' (
'ID' int(11) NOT NULL DEFAULT '0',
'name' char(10) DEFAULT NULL,
PRIMARY KEY ('ID')
)
The table mytable on the slave contains the following:

You have issued a STOP SLAVE command. 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 GLOBAL SQL_SKIP_SLAVE_COUNTER=1
B)
SET GTID_NEXT="CONSISTENCY";
BEGIN; COMMIT;
SET GTID_NEXT=" AUTOMATIC’;
C)
SET GLOBAL enforce_gtid_consistency=ON
D)
SET GTID_EXECUTED="38f32e23480a7-32a1-c323f78067fd37821 : 9";
E)
SET GTID_NEXT="38f32e23480a7-32a1-c323f78067fd37821 : 9";
BEGIN; COMMIT;
SET GTID_NEXT="AUTOMATIC";
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答案：
http://tieba.baidu.com/p/4118342106

2.
Consider the following statement on a RANGE partitioned table:
ALTER TABLE orders DROP PARTITION p1, p3;
What is the outcome of executing the above statement?
A.
Only the first partition (p1) will be dropped as only one can be dropped at any time.
B.
All data in p1 and p3 partitions are removed, but the table definition remains unchanged.
C.
A syntax error will result as you cannot specify more than one partition in the same statement.
D.
All data in pi and p3 partitions are removed and the table definition is changed.
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答案：
http://tieba.baidu.com/p/4118342106

5.
ROW-based replication has stopped working. You investigate the error log file and find the following entries:
2013-08-27 14:15:47 9056 [ERROR] Slave SQL: Could not execute Delete_rows event on table test.t1; Can’t find record in ‘t1’, Error_code: 1032; handler error HA_ERR_KEY_NOT_FOUND; the event’s master log 56_master-bin.000003, end_log_pos 851, Error_code: 1032
2013-08-27 14:15:47 9056 [warning] Slave: Can’t find record in ‘t1’ Error_code: 1032
2013-08-27 14:15:47 9056 [ERROR] Error running query, slave SQL thread aborted. Fix the problem, and restart the slave SQL thread with “SLAVE START”. We stopped at log ‘56_masterbin.000003’ position 684
Why did you receive this error?
A.
The slave SQL thread does not have DELETE privileges to execute on test.t1 table.s
B.
The table definition on the slave litters from the master.
C.
Multi-threaded replication slaves can have temporary errors occurring for cross database updates.
D.
The slave SQL thread attempted to remove a row from the test.t1 table, but the row did not exist.
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答案：http://tieba.baidu.com/p/4118342106

7.
Consider the Mysql Enterprise Audit plugin.
You are checking user accounts and attempt the following query:
Mysql> SELECT user, host, plugin FROM mysql.users;
ERROR 1146 (42S02): Table ‘mysql.users’ doesn’t exist
Which subset of event attributes would indicate this error in the audit.log file?
A.
NAME=”Query”
STATUS=”1146”
SQLTEXT=”select user,host from users”/>
B.
NAME=”Error”
STATUS=”1146”
SQLTEXT=”Error 1146 (42S02): Table ‘mysql.users’ doesn’t exist”/>
C.
NAME=”Query”
STATUS=”1146”
SQLTEXT=” Error 1146 (42S02): Table ‘mysql.users’ doesn’t exist”/>
D.
NAME=”Error”
STATUS=”1146”
SQLTEXT=”select user,host from users”/>
E.
NAME=”Error”
STATUS=”0”
SQLTEXT=”Error 1146 (42S02): Table ‘mysql.users’ doesn’t exist”/>
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答案：http://tieba.baidu.com/p/4118342106

8.
Which query would you use to find connections that are in the same state for longer than 180 seconds?
A.
SHOW FULL PROCESSLIST WHERE Time > 180
B.
SELECT * FROM INFORMATION_SCHEMA.EVENTS SHERE STARTS < (DATE_SUB(NOW(), INTERVAL 180 SECOND))
C.
SELECT * FROM INFORMATION_SCHEMA.SESSION_STATUS WHERE STATE < (DATE_SUB(NOW(), INTERVAL 180 SECOND))
D.
SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST WHERE TIME > 180;
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答案：http://tieba.baidu.com/p/4118342106

9.
A database exists as a read-intensive server that is operating with query_cache_type =
DEMAND.
The database is refreshed periodically, but the resultset size of the queries does not fluctuate.
—-Note the following details about this environment:
A web application uses a limited set of queries.
The Query Cache hit rate is high.
All resultsets fit into the Query Cache.
All queries are configured to use the Query Cache successfully.
The response times for queries have recently started to increase. The cause for this has correctly been identified as the increase in the number of concurrent users accessing the web service.
Based solely on the information provided, what is the most likely cause for this slowdown at the database level?
A.
The Query Cache is pruning queries due to an increased number of requests.
B.
Query_cache_min_res_unit has been exceeded, leading to an increased performance
overhead due to additional memory block lookups.
C.
Mutex contention on the Query Cache is forcing the queries to take longer due to its singlethreaded nature.
D.
The average resultset of a query is increasing due to an increase in the number of users
requiring SQL statement execution.
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答案：http://tieba.baidu.com/p/4118342106

10.
You have a login-path named "adamlocal" that was created by using the mysql_config_editor command.
You need to check what is defined for this login_path to ensure that it is correct for you deployment.
You execute this command:
$ mysql_config_editor print –login-path=adamlocal
What is the expected output of this command?
A.
The command prints all parameters for the login-path. The password is printed in plain text.
B.
The command prints all parameters for the login-path. The password is shown only when you provide the --password option.
C.
The command prints all parameter for the login-path. The password is replaced with stars.
D.
The command prints the encrypted entry for the login-path. The is only possible to see if an entry exists.
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答案：http://tieba.baidu.com/p/4118342106

11.
You are using replication and the binary log files on your master server consume a lot of disk space.
Which two steps should you perform to safely remove some of the older binary log files?
A.
Ensure that none of the attached slaves are using any of the binary logs you want to delete.
B.
Use the command PURGE BINARY LOGS and specify a binary log file name or a date and time to remove unused files.
C.
Execute the PURGE BINARY LOGE NOT USED command.
D.
Remove all of the binary log files that have a modification date earlier than today.
E.
Edit the .index file to remove the files you want to delete.

答案：http://tieba.baidu.com/p/4118342106

12.
Which two statements are true about InnoDB auto-increment locking?
A.
The auto-increment lock can be a table-level lock.
B.
InnoDB never uses table-level locks.
C.
Some settings for innodb_autoinc_lock_mode can help reduce locking.
D.
InnoDB always protects auto-increment updates with a table-level lock.
E.
InnoDB does not use locks to enforce auto-increment uniqueness.
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答案：http://tieba.baidu.com/p/4118342106

13.
Consider the Mysql Enterprise Audit plugin.
A CSV file called data.csv has 100 rows of data.
The stored procedure prepare_db() has 10 auditable statements.
You run the following statements in the mydb database:
Mysql> CALL prepare_db();
Mysql> LOAD DATA INFILE '/tmp/data.cav' INTO TABLE mytable;
Mysql> SHOW TABLES;
How many events are added to the audit log as a result of the preceding statements?
A.
102; top-level statements are logged, but LOAD DATA INFILE is logged as a separate event.
B.
3; only the top-level statements are logged.
C.
111; top-level statements and all lower-level statements are logged.
D.
12; only top-level statements and stored procedure events are logged.
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答案：http://tieba.baidu.com/p/4118342106