Bukkit/Spigot) Better MySQL stats updating no lag?

Question

Hi there I'm having issues with SQL updating player stats which makes very huge lag/timings drop I'm updating the stats on server stop this is my stats code:

public int getDeaths(Player p) {
    if (!plugin.getConfig().getBoolean("mysql")) {
        return plugin.data.getConfig().getInt("Deaths." + p.getUniqueId() + ".death");
    }
    if (plugin.getConfig().getBoolean("mysql")) {
        int res = 0;
        ResultSet result = getMainSQLConnection()
                .executeQuery("SELECT * FROM `Account` WHERE playername='" + p.getName() + "'", false);
        try {
            if (result.next()) {
                res = Integer.parseInt(result.getString("deaths"));
            }
        } catch (SQLException localSQLException) {
        }
        return res;
    }
    return 0;
}

public void setDeaths(Player p, int number) {
    if (!plugin.getConfig().getBoolean("mysql")) {
        plugin.data.getConfig().set("Deaths." + p.getUniqueId() + ".death", number);
        plugin.data.save();
    }
    if (plugin.getConfig().getBoolean("mysql")) {
        plugin.sqlConnection.executeUpdate(
                "UPDATE `Account` SET deaths='" + number + "' WHERE playername='" + p.getName() + "'");
    }
}

Answer 1

If you're getting the death count for a command or something that doesn't require the value to be returned immediately, use a asynchronous scheduler to run the code on a separate thread. For a command you'd do something like this when it is executed:

Bukkit.getScheduler().runTaskAsynchronously(plugin, () -> {
    try {
        int deaths = getMainSQLConnection()
                .executeQuery("SELECT * FROM `Account` WHERE playername='" + p.getName() + "'", false)
                .getInt("deaths");
        player.sendMessage("Player Deaths: " + deaths);
    } catch (SQLException ex) {
        player.sendMessage(ChatColor.RED + "That player does not exist!");
    }
});

Otherwise, if you need the value in the code for whatever reason, you can use a connection pool such as HikariCP. A connection pool will allow you to maintain multiple connections to your database so when you need to execute a query you don't have to establish a new connection every time (which is what will cause most of the lag).

Better yet, use an asynchronous task in tandem with the connection pool. Here's a good tutorial for learning how to use HikariCP with Bukkit: https://www.spigotmc.org/threads/tutorial-implement-mysql-in-your-plugin-with-pooling.61678

As a side note, for basically zero performance impact on the server, you can load the data asynchronously when a player logs in (using the AsyncPlayerPreLoginEvent). Then store it in memory when they actually join the server (PlayerLoginEvent or PlayerJoinEvent), and remove it when they quit. This way you access the data through memory while they're logged in rather than the database. This is much more complicated and also requires a lot of code to implement correctly though, so I'm not going to go into detail here.