https://www.drmhse.com/tags/sql/Recent content in Sql on DRM HSEHugoenSun, 07 Jun 2026 16:05:39 +0300https://www.drmhse.com/posts/check-then-act-race-condition/Thu, 20 Nov 2025 05:20:09 +0000https://www.drmhse.com/posts/check-then-act-race-condition/<p>Fast code does not forgive sloppy state changes. It exposes them.</p> <p>That is how a SAML certificate rotation feature turned into a concurrency bug. The API was written in Rust with <code>axum</code>, <code>SeaORM</code>, and PostgreSQL as the source of truth. The handler looked normal. The logic was easy to read.</p> <p>Under concurrent pressure, it failed immediately.</p> <p>The bug was the old one: <strong>Check-Then-Act</strong>.</p> <p>Read state. Make a decision. Write new state. Somewhere between those steps, another request sneaks in and makes the decision stale.</p>