golang process shutdown db

golang process shutdown db

With the widespread application of Golang, more and more applications are beginning to use Golang to process data, including database operations. So when we write Golang code, how to handle database connection and shutdown well?

In Golang, we can use the database/sql package in the standard library to perform database operations, which provides out-of-the-box functionality. Under normal circumstances, our code will involve the opening, use and closing of database connections. If not handled well, these connections will remain alive until the entire process exits, which will cause a certain waste of resources, even cause the database connection pool to be full, and produce some unexpected errors. So how do you close the database connection nicely?

1. Use the defer keyword

We can use the defer keyword in the code block that opens the connection to ensure that the closing method of the database connection is called before the function returns, code example As follows:

func dbOperations() error {

db, err := sql.Open("mysql", "user:password@tcp(host:port)/dbname")
if err != nil {
    return err
}
defer db.Close()
// 进行数据库操作
...
return nil

}

Using the defer keyword can ensure that we close the database connection before the function returns, so that the connection is closed before the program exits Close promptly. Without using the defer keyword, we need to explicitly call defer db.Close(), otherwise we will forget to close the connection. Therefore, in code that uses database connections, use the defer keyword whenever possible to manage the closing of the connection.

2. Set the maximum number of connections and the number of idle connections in the connection pool

Every time a connection is obtained from the connection pool, the connection pool will look for an available connection in the connection pool. connect. If no connection is available, a new connection is created and added to the connection pool. If too many connections are created in the connection pool, the connection pool may become full. We can avoid this situation by setting the maximum number of connections and the number of idle connections in the connection pool.

The following is an example of setting connection pool parameters:

db, err := sql.Open("mysql", "user:password@tcp(host:port)/dbname")
if err != nil {

return err

}
db.SetMaxIdleConns(10)
db.SetMaxOpenConns(100)

In this example, we pass the SetMaxIdleConns function Set the number of idle connections in the connection pool to 10, and the SetMaxOpenConns function sets the maximum number of connections in the connection pool to 100. The operations in this example avoid the need to create a new connection each time the connection pool is used, and also prevent the connection pool from exceeding the maximum number of connections.

3. Set the timeout for the connection

In actual applications, we often encounter the problem that the application cannot handle it correctly when the database server goes down. In this case, the connection will always be in a waiting state, and the program will waste resources. We can set a timeout for the connection to avoid this situation. The code example is as follows:

db, err := sql.Open("mysql", "user:password@tcp(host:port)/ dbname")
if err != nil {

return err

}
db.SetConnMaxLifetime(30 * time.Second)

In this example, we connect to the database through the SetConnMaxLifetime function A timeout is set, and when the life cycle of the connection exceeds the given time, it will be automatically closed. By setting the timeout for the connection, we can prevent the connection from waiting for a long time, thereby avoiding a waste of resources.

Summary

Database connections in Golang are a valuable resource, so we must manage and close them correctly. We can use the defer keyword and set connection pool parameters to ensure that the connection is closed before the function returns and prevent the connection pool from filling up. At the same time, we can prevent the connection from waiting for a long time by setting a timeout for the connection. Through these techniques, we can establish a more reliable and efficient database connection management mechanism.

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