考试题量：85

通过分数：62%

官方考试说明：产品目录-ouexam-pexam_1z0-908/pexam_1Z0-908

Q1.Examine this command, which executes successfully:

mysqlbackup --user=dba --password --port=3306 --with-timestamp --backup- dir=/export/backups backup-and-apply-log

Which statement is true?

A)The backup accesses the MySQL server files by using a pre-existing connection.

B)The database server is put into a read-only state for the duration of the backup. C)An offline backup of InnoDB tables is taken.

D)The backup can be impacted when DDL operations run during the backup.

Answer:D

参见《MySQL8.0 for Database Administrators studentGuide 2》243页

While the non-InnoDB backup runs:

— Prior to version 8.0.16, the database cannot be modified

— As of version 8.0.16, only non-InnoDB tables cannot be modified and InnoDB tables allow DML operations but not DDL operations

Q2.You reconfigure and start a slave that was not replicating for several days.

The configuration file and CHANGE MASTER command are correct. Examine the GTID information from both master and slave:

Master:
Gtids_executed: 
aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:1-321, 
bbbbbbbb-bbbb-bbbb-bbbbbbbbbbbb:1-50, 
Cccccccc-cccc-cccc-cccc-cccccccccccc:1234-1237
Gtids_purged: aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:1-100, 
bbbbbbbb-bbbb-bbbb-bbbbbbbbbbbb:1-10, 
cccccccc-cccc-cccc-cccc-cccccccccccc:1234-1237
Slave:
Gtids_executed: 
aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:1-160, 
cccccccc-cccc-cccc-cccc-cccccccccccc:1234-1237
Gtids_purged: aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:1-70, 
cccccccc-cccc-cccc-cccc-cccccccccccc:1234-1237

Which statement is true?

A)Replication will fail because the master does not have the required transaction with bbbbbbbb-bbbb-bbbb-bbbb-bbbbbbbbbbbb GTIDs in its binary logs.

B)Replication will fail because the  master has  already purged transactions    with cccccccc-cccc-cccc-cccc-cccccccccc GTIDs.

C)Replication will fail because of inconsistent numbers in cccccccc-cccc-cccc-cccc-cccccccccccc GTIDs.

D)Replication will fail because the slave has purged more aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa transactions than the master.

E)Replication will work. 

Answer:A

Q3.Which two authentication plugins require the plain text client plugin for authentication to work?

A)Windows Native authentication B)PAM authentication

C)LDAP SASL authentication D)LDAP authentication E)SHA256 authentication F)MySQL Native Password

Answer:BD

[https://dev.mysql.com/doc/refman/8.0/en/cleartext-pluggable-authentication.html](https://dev.mysql.com/doc/refman/8.0/en/cleartext-pluggable-authentication.html)

Q4.You want to log only the changes made to the database objects and data on the MySQL system. Which log will do this by default?

A)error log 

B)slow query log

C) general query log 

D)binary log

E)audit log

Answer:D

Q5.You have an installation of MySQL 8 on Oracle Linux. Consider the outputs:

Mysql>SHOW GLOBAL VARIABLES
WHERE Varisble_name=’tmpdir‘ OR Variable_name =’ tmp_table_size; 
+------------------+-----------+
| Variable_name |Value |
+------------------------+-----+
|tmp_tabe_size | 16777216|
|tmpdir | /tmp |
+-------------------+----------+
Shell>cd/var/lib/mysql Shell>ls -1|grep temp
Drwxr-x---.2 mysql mysql 4096 Dec 11 14:05 #innodb_temp

Which statement is true about disk temporary tables for this installation? 

A)Temporary tables are created in tmpdir only if configured to use MyISAM。 

B)Temporary tables are created in tmpdir only after they reach tmp_table_size. 

C)Temporary tables will use the InnoDB temporary tablespace located in datadir. 

D)Only internal temporary tables from the optimizer will be created in tmpdir.

E)Temporary tables will use the InnoDB temporary tablespace located in /tmp. 

Answer:C

超过tmp_table_size 和max_heap_table_size最小值的临时表创建到磁盘上。 Tmpdir目录下创建的是临时文件，默认是/tmp

InnoDB用户创建的临时表和磁盘上的内部临时表是在MySQL数据目录中名为ibtmp1的临 时表空间文件中创建的，是全局临时表空间。#innodb_temp 目录下是会话临时表空间 参见官方文档: 15.6.3.5 Temporary Tablespaces 在另外一个题库里选两个，就加上A。

Q6.Which two actions will secure a MySQL server from network-based attacks?

A)Use MySQL Router to proxy connections to the MySQL server. 

B)Place the MySQL instance behind a firewall.

C)Use network file system (NFS) for storing data. 

D)Change the listening port to 3307.

E)Allow connections from the application server only.

 Answer:BE