MSSQL leaking connections - sql-server

Question

I have strange issue with golang sql and probably denisenkom/go-mssqldb.
My code part:
func Auth(username string, password string, remote_ip string, user_agent string) (string, User, error) {
var token string
var user = User{}
query := `exec dbo.sp_get_user ?,?`
rows, err := DB.Query(query, username, password)
if err != nil {
return token, user, err
}
defer rows.Close()
rows.Next()
if err = rows.Scan(&user.Id, &user.Username, &user.Description); err != nil {
log.Printf("SQL SCAN: Failed scan User in Auth. %v \n", err)
return token, user, err
}
hashFunc := md5.New()
hashFunc.Write([]byte(username + time.Now().String()))
token = hex.EncodeToString(hashFunc.Sum(nil))
query = `exec dbo.sp_set_session ?,?,?,?`
_, err = DB.Exec(query, user.Id, token, remote_ip, user_agent)
if err != nil {
return token, user, err
}
return token, user, nil
}
Problem: defer rows.Close() - not working properly
After this with DB.Connection.Stats().OpenConnections I always have 2 connection opened (also after repeat User login is still 2 connection for whole app lifecycle)
But if I rewrite func as:
...
query := `exec dbo.sp_get_user ?,?`
rows, err := DB.Query(query, username, password)
if err != nil {
return token, user, err
}
defer rows.Close()
rows.Next()
if err = rows.Scan(&user.Id, &user.Username, &user.Description); err != nil {
log.Printf("SQL SCAN: Failed scan User in Auth. %v \n", err)
return token, user, err
}
rows.Close()
...
Then rows underline stmt is closed and next DB.Connection.Stats().OpenConnections always will be 1 connection open.
DB in my app is simply return underlying connection from sql.Open
Problem is only in this part where two query executions with Query and Exec in one functions.
Maybe Query and Exec defines different connections, but i don't find this in driver source or database/sql source.
Thank you! (sorry for english if it's so bad)
PS:
exec dbo.sp_get_user ?,? - is simple select from user table, not more.
exec dbo.sp_set_session ?,?,?,? - is simple insert to user table, not more
In MSSQL - DBCC INPUTBUFFER shows me query = 'cast(##identity as bigint)' which executes in denisenkom/go-mssqldb mssql.go on line 593