A database exists as a read-intensive server that is operating with query_cachek_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
您可能感兴趣的试卷
你可能感兴趣的试题
Mysqldump was used to create a single schema backup; Shell> mysqldump –u root –p sakila > sakila2013.sql
Which two commands will restore the sakila database without interfering with other running database?（）
A.Mysql＞ USE sakila; LOAD DATA INFILE 'sakila2013.sql';
B.Shell＞ mysql –u root –p sakila sakila2013.sql
C.Shell＞ mysql import –u root –p sakila sakila2013.sql
D.Shell＞ mysql –u root -p –e 'use sakila; source sakila2013.sql'
E.Shell＞ mysql –u root –p –silent ＜ sakila2013.sql
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
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.A syntax error will result as you cannot specify more than one partition in the same statement
B.All data in p1 and p3 partitions are removed and the table definition is changed
C.All data in p1 and p3 partitions are removed, but the table definition remains unchanged
D.Only the first partition (p1) will be dropped as only one can be dropped at any time
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 GTID_NEXT="CONSISTENCY"; BEGIN; COMMIT; SET GTID_NEXT="AUTOMATIC"
B.SET GLOBAL enforce_gtid_consistency=ON
C.SET GTID_EXECUTED="38f32e23480a7-32a1-c323f78067fd37821 : 9"
D.SET GTID_NEXT="38f32e23480a7-32a1-c323f78067fd37821 : 9"; BEGIN; COMMIT; SET GTID_NEXT="AUTOMATIC"
E.SET GLOBAL SQL_SKIP_SLAVE_COUNTER=1
最新试题
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?（）
Consider the MySQL Enterprise Audit plugin.On attempting to start the MySQL service after a crash, notice the following error: [ERROR] Plugin ‘audit_log’ init function returned error.In the audit log file, you notice the final entry:…What action should you take to fix the error and allow the service to start?（）
A general purpose MySQL instance is configured with the following options:—log-slow-queries—long-query-time=,0001—log-slow-admin-queries—general-log—log-bin—binlog-format=STATEMENT—innodb-flush-log-at-trx-commit=1Which three statements are true（）。
A MySQL replication slave is set up as follows: User all InnoDB tablesReceives ROW-based binary logs Has the read-only optionThe replication slave has been found in an error state.You check the MySQL error log file and find the following entries:2013-08-27 13:55:44 9056 [ERROR] Slave SQL: Could not execute Write_rows event on table test.tl; Duplicate entry ‘3’ for key’PRIMARY’ , Error_code: 1062; handler error HA_ERR_FOUND_DUPP_KEY; the event’s master log 56_master-bin.000003, end_log_pas 653, Error_code: 10622013-08-27 13:55:44 9056 [Warning] Salve: Duplicate entry ‘3’ for key ‘PRIMARY’Error_code: 10622013-08-27 13:55:44 9056 [ERROR] Error running query, slave SQL thread aborted. Fix theproblem, and restart the slave SQL thread with “SLAVE START”, We stopped at log ‘56_masterbin.000003’ position 496 What are two possible causes for this error to occur?（）
Consider the following:Which statement best describes the meaning of the value for the key_len column?（）
You have table 'apps','userdata' on server that uses MyISAM storage engine.You want to transfer this data to server but use InnoDB engine instead. You execute the following commands: ServerB commands:Shell＞ mysqldump –u root –h server –no-data apps userdata mysql –u root –p appsShell＞ mysql –u root –p –h server –e 'ALTER TABLE 'apps','userdata' ENGINE=InnoDB;'Shell＞ mysqldump –u root –p –h server –no-create-info –order-by-primary apps userdata mysql –u root –p appsWhat effect does the – order-by-primary argument have on the mysqldump command?（）
You have taken a Logical Volume Manager (LVM) snapshot backup of a volume that contains the MySQL data directory. Why is it important to remove snapshots after completing a RAW backup in this way?（）
You want to create a temporary table named OLD_INVENTORY in the OLD_INVENTORY database on the master server. This table is not to be replicated to the slave server.Which two changes would ensure that the temporary table does not propagate to the slave?（）
Which two options describe how MySQL Server allocates memory?（）
What are three facts about backups with mysqldump?（）