An index made our query faster. It slowly suffocated our database.

<p><em>B-tree internals, column order and planner statistics in Postgres 19, checked against MongoDB's ESR rule.</em></p> <p>Most "add an index" advice stops at <code>CREATE

<p>A news platform I maintain started serving pages in six seconds. Load average sat at 16 on a 12-core box for hours. Nothing had been deployed. Traffic was up, but not 10x

<p>PostgreSQL index design is often misunderstood.</p> <p>Many developers think that creating a good index simply means:</p> <blockquote> <p>“Create an index containing the

<h2> I Thought My Index Would Fix Everything </h2> <p>I added the index.</p> <p>Ran the query.</p> <p>And… nothing changed.</p> <p>Same slow response. Same frustration.</p>

<blockquote> <p>The pager went off at 2:14 AM.</p> </blockquote> <p>If you’ve spent any time operating distributed systems, you know that sound. It doesn’t just wake you up; it

<p>“It was fast… until users showed up.”</p> <p>That’s what I told a friend when we were debugging his system.</p> <p>Everything looked good at the start. Few users, Fast