A query with a hand-written optimiser hint from 2019, re-examined after an upgrade, where the hint was now choosing the worse plan. A hint is a decision frozen…
An index on (customer_id) alongside one on (customer_id, created_at), where the first is a prefix of the second and does nothing. Redundant indexes cost write throughput and buffer…
Laravel 11 allows a per-second limit, and applying one to an endpoint limited to sixty a minute showed what that had actually been permitting. A per-minute limit is…
A retention job deleting eleven million rows a month from a partitioned table, one batch at a time, without touching the partition boundary. The partitioning had been done…
An endpoint with a healthy p95 and one consumer for whom it was consistently slow. Aggregating across consumers averages away exactly the case that generates support tickets, and…