How can a server efficiently track and notify users who have not logged in for a certain period of time using PHP?

To efficiently track and notify users who have not logged in for a certain period of time using PHP, the server can store the last login timestamp for each user in the database. Then, the server can periodically check this timestamp against the current time to determine if a user has not logged in for a specified period. If a user has not logged in for the set duration, the server can send a notification to remind them to log in.

// Assume $lastLoginTimestamp is the timestamp of the user's last login stored in the database
// Set the duration in seconds for when a user is considered inactive (e.g. 30 days)
$inactiveDuration = 30 * 24 * 60 * 60; 

// Check if the user has not logged in for the specified duration
if(time() - $lastLoginTimestamp >= $inactiveDuration) {
    // Send a notification to the user
    $notificationMessage = "Reminder: Please log in to your account.";
    // Code to send notification (e.g. email, SMS, push notification)
}