Backend war stories, told properly.

Your Index Has Three Jobs. A Sort Can Break One of Them.

• Imad ALILAT
• August 25, 2026
• Intermediate

I showed a colleague a query reading 109 documents to return one, and the index it was supposed to be using. He looked at both and said the obvious thing: “that’s not even the same index. It’s got four fields, your query filters on three completely different ones.”

Two Billion Documents a Week to Produce a List of Numbers

• Imad ALILAT
• August 25, 2026
• Intermediate

One query. Seven days. Here’s what it cost.

JaVers From First Principles: How Automatic Audit Logging Actually Works

• Imad ALILAT
• August 24, 2026
• Beginner

Somebody asks who changed this invoice’s status last Tuesday, and from what. Your application has to be able to answer, and nobody wants to hand-write that logging on every setter.

Caffeine From First Principles: The Guarantee getIfPresent Doesn’t Make

• Imad ALILAT
• August 22, 2026
• Intermediate

Here’s a cache read. Three lines, no locks, nothing clever. It has a concurrency bug, and so does the identical code inside a library you may already depend on.

Your Feature Flag Bill Is a Cache Key Problem

• Imad ALILAT
• August 20, 2026
• Intermediate

A client exceeded their feature flag vendor’s monthly request quota by 100%.

The two fixes everyone proposed were delete the dead flags and stop calling flags inside loops. Both are sensible. Both save exactly zero requests.

The N+1 With No Query In It: JPA Fetch Types From First Principles

• Imad ALILAT
• August 12, 2026
• Intermediate

An export endpoint died at thirty seconds. Not degraded, died: the platform router gave up, the browser reported a CORS failure that had nothing whatsoever to do with CORS, and the UI showed a toast saying something went wrong.

I had three hypotheses inside twenty minutes of reading code. All three were wrong.