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Most people do not understand the knowledge points of this article "what is the concept of mysql Actuator?", so the editor summarizes the following content, detailed content, clear steps, and has a certain reference value. I hope you can get something after reading this article. Let's take a look at this "what is the concept of mysql Actuator" article.

Description

1. Call the API operation data of the storage engine.

2. After the optimizer completes the sql optimization, it provides the execution plan to the executor, and the executor begins to execute the execution plan to manipulate the data.

When you open a table, the executor uses the interface provided by the engine based on the engine definition of the table.

When you start to execute, you must first determine whether you have the right to execute the query for this table T. If not, you will return to the error of not having permission, as shown below.

In a project implementation, if you hit the query cache, you will validate permissions when the query cache returns results. Before the optimizer, the query also calls precheck to verify permissions.

Mysql > select * from test where id=1

For example, in our example, the ID field does not have an index, and the executor executes like this:

(1) call the InnoDB engine API to fetch the first row of the table to determine whether the ID value is 10. If not, skip it. If not, the result of the row.

(2) call the engine interface to fetch the next row and repeat the same judgment logic until you get the last row of the table.

(3) the executor returns the recordset composed of all qualified rows in the above traversal process to the client as a result set.

The above is the content of this article on "what is the concept of mysql Actuator". I believe we all have a certain understanding. I hope the content shared by the editor will be helpful to you. If you want to know more about the relevant knowledge, please pay attention to the industry information channel.

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