What are potential performance issues with the current PHP code for displaying online users?

The current PHP code for displaying online users may have performance issues if it queries the database frequently or performs complex calculations for each user. To improve performance, consider implementing caching mechanisms to store the online user data and reduce the number of database queries. 

// Example code snippet with caching mechanism for displaying online users

// Check if online user data is already cached
$online_users = get_transient('online_users');

// If not cached or cache is expired, query the database
if (false === $online_users) {
    $online_users = get_online_users_from_database();

    // Cache the online user data for 1 minute
    set_transient('online_users', $online_users, 60);
}

// Display online users
foreach ($online_users as $user) {
    echo $user['username'] . '<br>';
}

Keywords

MySQL queries caching session management server load database optimization

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