Ping() not working

[luca-moser]

Hi, I am currently facing a problem with the Ping() method in the SQL package, when using this driver. It seems that Ping() suceeds no matter what.

I have some little test code:

package main

import (
    "database/sql"
    "fmt"
    "time"
    _ "github.com/denisenkom/go-mssqldb"
)

func main() {

    connString := fmt.Sprintf("server=%s;user id=%s;password=%s;port=%d;database=%s;log=1",
        "host", "username", "password", 1433, "databasename")
    conn, err := sql.Open("mssql", connString)
    if err != nil {
        panic(err)
    }

    err = conn.Ping()
    if err != nil {
        fmt.Println("ping and reconnect failed:", err.Error())
        return
    }
    fmt.Println("connection to mssql database server ok")

    <-time.After(time.Duration(10) * time.Second)

    fmt.Println("pinging again database server...")
    err = conn.Ping()
    if err != nil {
        fmt.Println("ping and reconnect failed:", err.Error())
        return
    }
    fmt.Println("connection to mssql database server ok")
}

When I run this code and remove the network cable on my laptop when the waiting is going on <-time.After(time.Duration(10) * time.Second), the second pinging still succeeds with: "connection to mssql database server ok", although the database server is physically not reachable (my wireless adapter is deactivated btw).

I am using Ping() to check wether the database server is still online and to automatically re-connect to it. From the godoc of database/sql it states: "Ping verifies a connection to the database is still alive, establishing a connection if necessary.". My apps crash/throw errors on the first workday each week, because we usually restart our database server on the weekends.

Note: If I run this program with no network connection from the beginning it fails up on the first Ping(). It looks like subsquential Ping() don't report correctly.

Note 2: If using conn.SetConnMaxLifetime(time.Duration(3) * time.Second) in this code, the second Ping() will fail as it should.

[dimdin]

The driver has no control. The golang Ping implementation reuses the last connection from the pool. see: https://golang.org/src/database/sql/sql.go?s=14098:14124#L489

[luca-moser]

I see, thanks for the heads up.