Easily implement database connection pool using Go language

Go language is an open source and efficient programming language, which is very suitable for network programming and concurrent programming. In the Go language, database connection pool is a very important concept, which can improve the efficiency of database operations and save system resources.

This article will introduce how to use Go language to easily implement a database connection pool, including how to initialize the connection pool, how to obtain the connection, how to return the connection, etc.

1. Initialize the connection pool

In the Go language, we can use sync.Pool to implement the connection pool. sync.Pool is a concurrent and safe object pool implementation built into the Go language, which can store and reuse objects of any type. We can use sync.Pool to implement database connection pooling.

First, we need to define the connection pool object:

type MySQLPool struct {
    pool *sync.Pool
    connector func() (*sql.DB, error)
}

Among them, pool is a sync.Pool object, and connector is a function to connect to the database. The connector function returns an object of type *sql.DB and an error object, representing the result of connecting to the database.

Next, we need to initialize the connection pool:

func NewMySQLPool(connector func() (*sql.DB, error)) *MySQLPool {
    return &MySQLPool{
        pool: &sync.Pool{
            New: func() interface{} {
                db, err := connector()
                if err != nil {
                    panic(err)
                }
                return db
            },
        },
        connector: connector,
    }
}

In the above code, we use the NewMySQLPool function to initialize the connection pool. Its parameter is a function connector, used to connect to the database.

We created a sync.Pool object, and its New field is a function used to create a new connection. In this function, we call the connector function to connect to the database and return the connection. If the connection fails, we will throw a panic exception.

It should be noted here that we do not limit the size of the connection pool. In the Go language, the size of sync.Pool is automatically adjusted. When there are too many objects in the Pool, the Pool will dynamically reduce the number of objects to ensure that the number of objects in the pool is small. Therefore, we don't need to manually control the connection pool size.

2. Obtain the connection

After the connection pool initialization is completed, we can use the database connection. We use the Get function to obtain the connection.

func (p *MySQLPool) Get() *sql.DB {
    return p.pool.Get().(*sql.DB)
}

Get function returns sql.DB object. We use interface type assertions to convert an object of type interface{} into an object of type sql.DB.

Before obtaining a connection, we need to ensure that the database connection pool has been initialized. We can call the NewMySQLPool function in the main function to initialize the connection pool.

func main() {
    pool := NewMySQLPool(func() (*sql.DB, error) {
        return sql.Open("mysql", "user:password@tcp(127.0.0.1:3306)/dbname")
    })
    defer db.Close()
}

In the above code, we use the NewMySQLPool function to initialize the connection pool. We will connect to the MySQL database with the user name user, password password, address 127.0.0.1, port 3306, and database name dbname. We can put this string in the configuration file to improve the maintainability of the code.

After the database connection pool is initialized, we can use the Get function to obtain the connection.

db := pool.Get()
defer db.Close()

Here, we use the defer keyword to return the connection to the connection pool. In this way, even if an exception occurs when executing a SQL statement, the connection will be correctly returned to the connection pool to avoid connection leaks and resource waste.

3. Return the connection

After the connection is used, we need to return the connection to the connection pool. We use the Put function to return the connection.

func (p *MySQLPool) Put(db *sql.DB) {
    p.pool.Put(db)
}

The parameter of the Put function is an object of type *sql.DB, which will put this object back into the connection pool. The implementation of this function is very simple, because sync.Pool comes with the Put function.

After using the connection, we need to return the connection to the connection pool. We can use the defer keyword to ensure that the connection is returned correctly.

db := pool.Get()
defer pool.Put(db)

Here, we first use the Get function to obtain a connection, and then automatically call the Put function at the end of the function to return the connection to the connection pool.

4. Summary

This article introduces how to use Go language to easily implement database connection pool. We use sync.Pool to implement the connection pool, use the Get function to obtain the connection, and the Put function to return the connection. This implementation is very simple, has a small amount of code, and is also very efficient.

Using the database connection pool can greatly improve the efficiency of database operations and reduce resource consumption. In Go language, it is very easy to implement connection pooling easily using sync.Pool. We hope this article can help you better understand and apply connection pooling technology in Go language.

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