Golang Mysql connectex套接字块

Question

I use the "go-sql-driver/mysql" driver. I have a product table that has a few dependencies. So i Select the product and get dependencies that would create cartesian products in subqueries. Usually there is a 200 products limit to have a better performance but in rare cases the limit will be removed or raised to lets say 3000-5000 then then i will get the following error:

dial tcp 127.0.0.1:3306: connectex: Normalerweise darf jede Socketadresse (Protokoll, Netzwerkadresse oder Anschluss) nur jeweils einmal verwendet werden.

which basically means:

connectex: Use every Socketaddress only once.

This is a snipped from my code, basically all my query-functions are build like that:

mysql := this.DBController.Connect()
defer mysql.Close()
.
.
.
for rows.Next() {
    err := rows.Scan(&x, &y, &z)
    if err != nil {
        log.Println("DBFetchMachines: Scan Error")
        log.Println(err)
    }
    product.PurchasePrice = this.priceR.DBFetchPurchasePriceByProductID(product.ID)
    product.SellingPrice = this.priceR.DBFetchSellingPriceByProductID(product.ID)
    product.DealerContact = this.contactR.DBGetBasicContact(product.DealerContact.ID)
    .
    .
    .
}

When i just query 200-1000 rows there is no issue. Is this maybe a OS related issue? I use Win10 64Bit as my dev machine.

Answer 1

As reticentroot in the comments suggested i checked alexedwards.net/blog/organising-database-access for some best practices examples. I choose Dependency injection and it works like a charm.