多项选择题

Which three statements are true about memory buffer allocation by a MySQL Server?（）

A.Global buffers such as the InnoDB buffer pool are allocated after the server starts, and are never freed
B.Thread buffers are allocated when a client connects, and are freed when the client disconnects
C.Buffers that are needed for certain operation are allocated when the operation starts, and freed when it ends
D.User buffers are allocated at server startup and freed when the user is dropped
E.All dynamic buffers that are set with a SET GLOBAL statement immediately get allocated globally, and are never freed

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热门试题

单项选择题Consider the following: Which statement best describes the meaning of the value for the key_len column?（）

A.It shows the total size of the index row
B.It shows how many columns in the index are examined
C.It shows the number of characters indexed in the key
D.It shows how many bytes will be used from each index row

单项选择题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?（）

A.Bob has max_user_connections set to zero, which blocks all his connections
B.Joe has exceeded the max_user_connections global limit
C.All users are blocked because max_user_connections is accumulated over the host account information
D.Kay is already connected elsewhere and attempting to log in again
E.Connect_timeout is too small to allow a connection to occur

单项选择题Your developers have created table to store some of their programs 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?（）

A.Convert the column to TEXT and add a fulltext index to the table
B.Create multiple prefix indexes of differing lengths
C.Convert their column to BINARY
D.Redesign the table so that the most commonly searched for string patterns are in their own columns

多项选择题Which three are properties of the MyISAM storage engine?（）

A.Transaction support
B.FULLTEXT indexing for text matching
C.Table and page level locking support
D.Foreign key support
E.Geospatial indexing
F.HASH index support
G.Table level locking only

多项选择题You need to replicate a table from a master to a slave. The master and slave copies of the table will have different number of columns. Which two conditions must be true?（）

A.Each extra column in the copy with more columns must not have a default value
B.Columns that are common to both versions of the table must be defined in the same order on the master and the slave
C.The slave database cannot have more columns than the master. Only the master database can have more columns
D.Columns that are common to both versions of the table must come first in the table definition, before any additional columns are additional columns are defined on either server
E.The master database cannot have more columns than the slave. Only the slave deatbase can have more columns