Tag: queryplanning

• The Real Cost of Random I/O in Spatial Queries

  Plan flips are normal in a cost-based optimizer, until they are not. The recent Clerk incident put attention back on a painful failure mode: a query crossing into a much worse plan after statistics/cost assumptions shift, causing a database outage. This post explores one specific driver of that risk in PostGIS workloads: miscalibrated random_page_cost, often…

  sburq

  March 16, 2026

  postgresql

  postgis, postgresql, queryplanning, tuning