High SeverityTransaction IntegrityLifecycle Management

Orphaned Cart Syndrome

1.The Symptom (The Chaos)

The database is cluttered with thousands of 'Ghost Carts' abandoned sessions that never expire causing massive slow-downs during checkout and increasing latency for active users.

2.The Trigger Condition

Users consistently abandon their carts without checking out, but the system lacks an automated lifecycle policy to expire these sessions, causing the database to grow indefinitely with stale data.

3.The Catch (Why it broke)

We relied on the database's natural storage capacity as a 'set-and-forget' repository, assuming that idle, abandoned records would simply remain dormant without impacting system performance.

4.Architectural Trade-offs

By implementing a recurring cleanup task, we maintain optimal database performance and query speed. However, we must carefully tune the batch size and scheduling frequency to ensure that these background deletions do not lock tables or compete for resources during peak user traffic.

CartServiceImpl.java

[Vulnerable Target View]

// VULNERABLE Causes N+1 performance degradation and potential OOM (Out of Memory)
@Scheduled(cron = "0 0 2 * * *")
@Transactional
public void cleanupAbandonedCarts() {
    // PROBLEM 1 Fetches ALL carts into memory. 
    // If 100k carts are abandoned, this crashes the JVM (Heap space).
    List<Cart> allCarts = cartRepository.findAll(); 
    for (Cart cart : allCarts) {
        if (cart.getUpdatedAt().isBefore(LocalDateTime.now().minusDays(1))) {
            // PROBLEM 2 N+1 Deletes. 
            // Every call to 'delete' sends a separate network packet to the DB,
            // locking the table row-by-row and ballooning transaction logs.
            cartRepository.delete(cart); 
        }
    }
}