(userId_eventType, timeRange)</code></li>
</ul>
<h3 class="anchor anchorWithStickyNavbar_LWe7" id="built-in-guardrails">Built-in Guardrails<a href="#built-in-guardrails" class="hash-link" aria-label="Direct link to Built-in Guardrails" title="Direct link to Built-in Guardrails">​</a></h3>
<p>Since Redis was the sole store, we implemented High Availability (HA) to prevent data loss. To optimize memory usage, we also enforced size limits per event type—only storing the last k interactions per user, with o