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