MySQL + spring database isolation level and performance analysis

Here, take MySQL as an example to clarify the following issues:

I If a general project does not configure transactions by itself, the default is autocommit, that is, automatically commit and commit transactions after an operation.

(Note: transactions are bound to database operations, that is, when the program executes (statement. Extract and other operations) the transaction only starts when it is transferred to the database level.) of course, spring can bind several database operations into one transaction, so it is necessary to introduce the spring transaction configuration methods. The following are common methods, and there are many other methods on the Internet. Spring provides many transaction configuration strategies, which are very convenient and brief Let me introduce: