对等方重置 Gorm 和 Postgres 连接

Question

Context

Currently I have a REST API that manages customer's data in a db. I'm using the following stack:

• Go 1.13

• github.com/jinzhu/gorm v1.9.1

• Postgres 11

I have the following connection settings.

// NewConnection ...
func NewConnection() (*gorm.DB, error) {
    config := getConfig()
        connStr := "host=xx.xx.xx port=5432 user=chavista-hatter dbname=my-db password=abc sslmode=verify-ca sslrootcert=/path/to/rcert sslcert=/path/to/cert sslkey=/path/to/key connect_timeout=0"
    db, err := gorm.Open("postgres", conn)
    if err != nil {
        return nil, err
    }

    db.DB().SetMaxOpenConns(25)
    db.DB().SetMaxIdleConns(25)
    db.DB().SetConnMaxLifetime(5 * time.Minute)

    db.SingularTable(true)

    if config.LogQueries {
        db = db.Debug()
    }

    return db, nil
}

I get a connection in the main class and inject that connection into a repository class that executes the queries through Gorm (ORM)

Main class

db, err := database.NewConnection()
    if err != nil {
        panic(fmt.Sprintf("failed to connect database --> %v", err))
    }
    fmt.Println("database connection established successfully")

defer db.Close()

customerRepo := customer.NewRepository(db)

Repository class

type repository struct {
    db *gorm.DB
}

//NewRepository 
func NewRepository(db *gorm.DB) Repository {
    return &repository{
        db: db,
    }
}

func (r *repository) Register(customer *models.Customer) (string, error) {

    err := r.db.Create(&customer).Error
    if err != nil {
        return "", err
    }

    return customer.key, nil
}

Problem

I sending over 500k request (INSERTS) to my db which have 512 connections available and after a few minutes the following error starts to come up repeatedly in postgres log:

unexpected EOF on client connection with an open transaction 
could not receive data from client: Connection reset by peer

Any help?

Answer 1

How are you using GetConnection in your code? It's creating a new connection pool every time it's called - ideally you'd only want to call it once, and pass that single connection around wherever it's used.

I would try changing it to this:

var db *gorm.DB
func NewConnection() (*gorm.DB, error) {
    if db != nil {
        return db, nil
    }
    config := getConfig()
    connStr := "host=xx.xx.xx port=5432 user=chavista-hatter dbname=my-db password=abc sslmode=verify-ca sslrootcert=/path/to/rcert sslcert=/path/to/cert sslkey=/path/to/key connect_timeout=0"
    var err error
    db, err = gorm.Open("postgres", conn)
    if err != nil {
        return nil, err
    }

    db.DB().SetMaxOpenConns(25)
    db.DB().SetMaxIdleConns(25)
    db.DB().SetConnMaxLifetime(5 * time.Minute)

    db.SingularTable(true)

    if config.LogQueries {
        db = db.Debug()
    }

    return db, nil
}

and see if it solves the issue.