Juan Manuel Ahumada Vázquez — WritingNotes from the field — incidents, architecture, and what AI agents do to my workflow.https://juanahumada.com/en-usWhen indexing isn't enough: a 4.2M-row deadlock fixhttps://juanahumada.com/en/writing/4m-row-deadlock-lessons/https://juanahumada.com/en/writing/4m-row-deadlock-lessons/A composite index that reduced a full-scan from 4.2M to 34 rows, and the query rewrite that made the index usable.Wed, 15 Apr 2026 00:00:00 GMTdatabasesmysqlperformanceCuando indexar no basta: el fix de un deadlock de 4.2M filashttps://juanahumada.com/es/writing/4m-row-deadlock-lessons/https://juanahumada.com/es/writing/4m-row-deadlock-lessons/Un índice composite que redujo un full-scan de 4.2M a 34 filas, y la reescritura de query que hizo el índice utilizable.Wed, 15 Apr 2026 00:00:00 GMTbases-de-datosmysqlperformanceOffline-first sync for field operations under intermittent connectivityhttps://juanahumada.com/en/writing/offline-first-field-ops/https://juanahumada.com/en/writing/offline-first-field-ops/Architecture and design decisions for a field app that has to stay functional through full connectivity, low signal and complete offline periods.Fri, 20 Mar 2026 00:00:00 GMTarchitectureoffline-firstresilienceSync offline-first para operaciones de campo bajo conectividad intermitentehttps://juanahumada.com/es/writing/offline-first-field-ops/https://juanahumada.com/es/writing/offline-first-field-ops/Arquitectura y decisiones de diseño para una app de campo que tiene que mantenerse funcional en condiciones de conectividad completa, baja señal y offline total.Fri, 20 Mar 2026 00:00:00 GMTarquitecturaoffline-firstresiliencia