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1.
In the following query, the Population column is indexed:
mysql> EXPLAIN SELECT Name
-> FROM Country
-> WHERE Code LIKE '%B%' AND Population > 10000 \G
************************** 1. row ***************************
id: 1
select_type: SIMPLE
table: Country
type: ALL
possible_keys: i_pop
key: NULL
key_len: NULL
ref: NULL
rows: 239
Extra: Using where
Which of the following best describes how to deal with the key value of the EXPLAIN output?
2.
Consider the following:
mysql> EXPLAIN SELECT DISTINCT City.id,City.name
-> FROM City,Country
-> WHERE Country.Name IN ('United States','Canada','Mexico')
-> AND City.CountryCode=Country.Code
-> ORDER BY name\G
************************** 1. row ***************************
id: 1
select_type: SIMPLE
table: City
type: ALL
possible_keys: NULL
key: NULL
key_len: NULL
ref: NULL
rows: 4079
Extra: Using temporary; Using filesort
************************** 2. row ***************************
id: 1
select_type: SIMPLE
table: Country
type: eq_ref
possible_keys: PRIMARY
key: PRIMARY
key_len: 3
ref: world.City.CountryCode
rows: 1
Extra: Using where; Distinct
Which of the following best describes the meaning of the values in the ref columns?
3.
Which of the following statements about MEMORY tables are true?
4.
The type of file system you chose may affect MySQL use and/or performance with regard to...
5.
Consider the following:
mysql> EXPLAIN SELECT * FROM City WHERE Name = 'Jacksonville' AND CountryCode
='USA'\G
************************** 1. row ***************************
id: 1
select_type: SIMPLE
table: City
type: ref
possible_keys: name_country_index
key: name_country_index
key_len: 13
ref: const,const
rows: 1
Extra: Using where
Which of the following best describes the meaning of the value for the key_len column?
6.
When should you enable the Query Cache?
7.
Consider the following:
mysql> EXPLAIN SELECT * FROM City WHERE CountryCode = 'USA'\G
************************** 1. row ***************************
id: 1
select_type: SIMPLE
table: City
type: ALL
possible_keys: NULL
key: NULL
key_len: NULL
ref: NULL
rows: 4079
Extra: Using where
Which of the following best describes the meaning of the "id" column in the output from EXPLAIN?
8.
Which of the following best describes the purpose of the record buffer (as controlled through the
read_buffer_size variable), and how it is set?
9.
Which of the following best describe the effects on performance for the dynamic-row format for
MyISAM has?
10.
Which of the following best describes what you might expect after disabling InnoDB at run time?