https://rollupdb.com/tags/explainer/ Recent content in Explainer on RollupDB.com Hugo en-us Sat, 17 Oct 2026 00:00:00 +0000 https://rollupdb.com/what-an-aggregate-database-keeps-when-the-raw-events-are-gone/ Sat, 17 Oct 2026 00:00:00 +0000 https://rollupdb.com/what-an-aggregate-database-keeps-when-the-raw-events-are-gone/ <p>Most databases keep what you put in. An aggregate database doesn&rsquo;t. It keeps what you&rsquo;ll ask about later, and only that. You tell it up front: for this stream of latencies, I want the count, the sum, the min and max, the mean, the variance and the 99th percentile, grouped by service. Then it&rsquo;s free to throw the individual readings away, because it already has what those readings were going to be used for.</p>