Oracle认证考试1z0-883章节练习(2019.03.25)

You are investigating the performance of the server and see the following information: Events_waits_summary_global_by_event_name in the performance schema shows that the wait/synch/mutex/sql/LOCK_table_cache event is dominating other wait events. The table_open_cache_overflows status variable is 0.
Which action should be taken to remove the performance bottleneck described here?（）

You use—login-path to access a MySQL server on a Linux installation.
Which statement is true about the – login-path option that is created by using mysql_config_editor?（）

An employee cannot access the company database. You check the connection variables:

What is a valid explanation for why one of the users is unable to connect to the database?（）

You have a server that has very limited memory but has a very large table. You will use mysqldump to back up this table.
Which option will ensure mysqldump will process a row at a time instead of buffering a set of rows?（）

A Mysql instance is running on a dedicated server. Developers access the server from the same network subnet. Users access the database through an application that is running on a separate server in a DMZ.
Which two will optimize the security of this setup?（）
 

Your developers have created table to store some of their program's data.
After examining the slow Query Log, you see that they are using the LIKE operator and SUBSTER () functions against a VARCHAR (10000) column quite often.
An example of the start of one row of data: 'GREEN01020495888331993-12-10/2…'
What should you do to improve the overall performance?（）

Consider the following:

Which statement best describes the meaning of the value for the key_len column?（）

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?（）