MYSQL 5.6 OCP 题库标准答案 1Z0-883

李鸿祥

2818

85页

2次

2020-07-17

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芬达 cjc44020 2019-10-14

KK 2019-10-11

前言

题目基于网上流出的题库整理，来源于"1Z0-883V9.025.6DBA.pdf"

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答案均为作者整理，自认为正确率较高

为了激发读者自主学习性，答案不提供解题思路和过程

本文档修复了"1Z0-883V9.025.6DBA.pdf"的各种错误，包括标点符号、拼写错误、大小写错误、

逻辑错误，并且进行了重新排版，尽量去掉图片，换成可以方便复制和测试的SQL语句，花费了大量

的时间。本文档不收费，如有错误之处欢迎指出。欢迎打赏，有技术问题也可以咨询我，欢迎添加作

者微信。

约定

都是5.6的答案，5.7答案有区别时会有特别指出

开始

1.ConsideratotalandsustainedfailureofthediskonwhichtheMySQLdatadirectory

resides.

WhichthreeHighAvailabilityscenariosareresilienttothiscase?

A.active/passiveDistributedReplicatedBlockDevice(DRBD).

B.standardmaster-slavereplication

C.MYSQLserviceforWindowsCluster

D.MySQLNDBCluster

E.OracleSolarisCluster

解释:

经常硬盘故障，那就要选择基于复制的高可用架构，保证数据有冗余不丢失，才是合适的高可用。

A.是磁盘复制；B.标准主从复制；D.NDB底层的每个node可以存一部分数据，或者完整的数据(根据

配置)

C、E均是基于共享存储的高可用。

2.Youwanttostartmonitoringstatisticsonthedistributionofstorageenginesthatare

beingusedandtheaveragesizesoftablesinthevariousdatabases.Somedetailsareas

follows:

TheMySQLinstancehas400databases.

Eachdatabaseonanaverageconsistsof25-50tables.Youusethequery:

SELECTTABLE_SCHEMA,

`ENGINE`,COUNT(*),

SUM(data_length)total_size

FROMINFORMATION_SCHEMA.TABLES

WHERETABLE_TYPE='BASETABLE'

GROUPBYTABLE_SCHEMA,ENGINE;

Whyisthisqueryslowtoexecute?

A.CountingandsummarizingalltablepagesintheInnoDBsharedtablespaceistime

consuming.

B.Collectinginformationrequiresvariousdisk-leveloperationsandistimeconsuming.

C.Aggregatingdetailsfromvariousstorageenginecachesforthefinaloutputistime

consuming.

D.Collectinginformationrequireslargenumbersoflocksonvarious

INFORMATION_SCHEMAtables,therebycausingcontention.

3.Adatabaseexistsasaread-intensiveserverthatisoperatingwithquery_cache_type=

DEMAND.Thedataset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.

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