https://hivion.ai/blog/ Field notes on data platforms, pipelines, and AI agents - written from systems we actually built. en https://hivion.ai/blog/the-partition-key-that-cost-60000-a-month/ https://hivion.ai/blog/the-partition-key-that-cost-60000-a-month/ Sat, 22 Aug 2026 09:00:00 +0000 A pipeline that never failed, never alerted, and quietly got more expensive for a year. What a historical load did to a Delta merge, and how we found it.