https://frn.sh/c/database/Recent content in Database onHugoen-USCopyright © Fernando Simões.Sun, 08 Feb 2026 00:00:00 +0000https://frn.sh/iops/Sun, 08 Feb 2026 00:00:00 +0000https://frn.sh/iops/We had a Postgres incident this week. Heroku timeouts, multiple queries running for 30+ minutes, and the IOPS pinned at the provisioned limit. I knew I needed a better index, but I wanted to understand what “reading from disk” actually means first. How many layers of caching sit between a SELECT and the storage device? Three. First: shared buffers, Postgres’ own cache living in the process memory. If the page is there, we need no system call - just a memory read.