After the table is indexed, sql can select the right index when the amount of data is small, but when the amount of data becomes large, it cannot select the correct index. We analyze the reasons for mysql’s wrong index selection from the following aspects. Impact the execution of sql cost analysis A ... More >>

About Online DDLDDL(Data Definition Language), that is, the data definition language, including new table, table add fields, change fields and other operations.Large table DDL at will execute dozens of minutes, even a few hours, such a long time to lock the table for the business is obviously unacce ... More >>