Unity MySQL lag

Unity Engine
,
1

Hello,

I have a problem with my Unity together with MySql, I need every 1 second to get data from the database, but when he opens the connection the game crashes.

Code:

    void CheckVersion(){
        MySqlConnection conn = new MySqlConnection(LinhaMySQL);
        try
        {
            conn.Open();
            string sql = "SELECT VERSION FROM servidor";
            MySqlCommand cmd = new MySqlCommand(sql, conn);
            object result = cmd.ExecuteScalar();
            cmd.CommandTimeout = 0;
            if (result != null)
            {
                MySqlDataReader reader = cmd.ExecuteReader();
                while(reader.Read())
                {
                    string versionserver = reader["VERSION"].ToString();
                    if(Application.version == versionserver) {
                        Debug.Log("Atualizado!");
                    } else {
                        if(LoginGUI.activeSelf == true) {
                            MessageShow("VersĂŁo desatualizada, atualize seu jogo.", "FECHAR");
                            //Debug.Log("Desatualizado!");
                        }
                    }
                }
            }
        }
        catch (Exception ex)
        {
            if(LoginGUI.activeSelf == true) {
                MessageShow("NĂŁo foi possĂ­vel se conectar com o servidor!", "FECHAR");
            }
        }
        conn.Close();
    }

Please help me :frowning:

Translated by Google Translate.

2

Pretty sure this has to be done asynchronously, which means:

  • using a coroutine for this access.
  • yielding inside your busy-wait loops.

When you do a while(true) kinda loop in Unity, pretty much NOTHING ELSE runs, which means you lock up. That’s why you make it a coroutine and yield.

3

I haven’t used this method before, but from a quick glance, it looks like it may be something to do with using two execute commands.

@Kurt-Dekker is right and you should always try and use the async operations.

If the object is not null, you should just be able to just cast it to a string. And not have to do the second execution. So long as the field you want is of the first column. I may be wrong though, have not used this way before.

You could use Visual Studio to debug, enter a breakpoint at the start of the function, and step through until you find what causes the crash.

Also, just an option… I would recommend using Dapper for any Databasing work when ADO/EF6 is not an option.
I personally like Dapp-Contrib as I started out with ADO. But there are several options to choose from.
https://dapper-tutorial.net/dapper

4

Thanks for the answer!

5

Additionally you should pool the connection and not reconnect every second. Perhaps try to call only once the method CheckVersion() in a Unity start() method and check by the debugger whats going on.

6

To be honest, just do not connect to MySQL from Unity applications ever, unless you’re developing some in-house simulator of some sort.

  • If you’re planning to distribute your application, connecting to a central database is extremely dangerous this way. If you need a central DB, put a layer (PHP or Python or whatever) between the two and just call REST endpoints.
  • If you want a local database, MySQL is too heavy for a game-like application, you are better off with some NoSQL lightweight solution.
1 Like
7

@ is spot on, but I kinda assumed you were connecting to a database built into your app, which of course necessitates putting it in StreamingAssets, and on certain targets (like Android) requires you to copy it OUT of your StreamingAssets and into a local temporary file for opening.

8

It only connects once, but it hangs when it calls the command.

Thanks for the answer!

9

Thanks for the answer!

10

it would also be interesting to know the answer to your problem