[Patrick]

Well converting from StrickenKid's will be different because r39 threaded and they aren't similar to the old one which I am referring to r6, I suggest you to read this https://sampwiki.blast.hk/wiki/MySQL/R33 and this https://sampforum.blast.hk/showthread.php?tid=337810 those link will help you a lot! so this is the code.

pawn Code:

new 
    rCheck[MAX_PLAYERS]; // declare a per-player array/var.

//Under OnPlayerConnect 
++ rCheck[playerid];

//Under OnPlayerDisconnect
++ rCheck[playerid];


//Sends a query which will be executed in another thread and calls the callback (if there is one) when the execution is finished.
mysql_tquery(connectionHandle, "SELECT * FROM `characters` WHERE `Activated` = 0 AND `Deletable` = 0 AND `DenialReason` = 'DenialReason' LIMIT 1", "OnCharactersLoad", "ii", playerid, rCheck[playerid]);

forward OnCharactersLoad(playerid, race_check);
public OnCharactersLoad(playerid, race_check)
{
    new 
        rows = cache_num_rows();

    if(rCheck[playerid] != race_check) //if the race_check 
        return Kick(playerid), printf("Invalid Race Check: rCheck[playerid]: %i - race_check:%i", rCheck[playerid], race_check);

    if(rows) //if rows is more than one, we proceed loading player's status.
    {
        cache_get_field_content(0, "CharacterName", destination, connectionHandle = 1, sizeof(destination));
        //and so on loading
    }
    return true;
}

Why does race_check needed?

Quote:

Originally Posted by maddinat0r race condition check: player A connects -> SELECT query is fired -> this query takes very long while the query is still processing, player A with playerid 2 disconnects player B joins now with playerid 2 -> our laggy SELECT query is finally finished, but for the wrong player what do we do against it? we create a connection count for each playerid and increase it everytime the playerid connects or disconnects we also pass the current value of the connection count to our OnPlayerDataLoaded callback then we check if current connection count is the same as connection count we passed to the callback if yes, everything is okay, if not, we just kick the player