A field that had to change from text to keyword, which is not an update. A mapping is append-only for existing fields, which is the constraint that makes…
An index created for a reporting query, and the report replaced by a projection four weeks afterwards. An index nobody reads costs write throughput and buffer pool on…
A rebuild time short enough that the index stops being something to protect. A derived store that can be rebuilt quickly does not need a backup, which removes…
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…
A search index that had been incrementally updated for three years, with no test that the increments were correct. The diff is the point rather than the rebuild…
A search document carrying the full product description as both an indexed text field and a stored copy, on a catalogue where descriptions run to several pages. The…
A status column where one value covers ninety-four per cent of rows, and an optimiser assuming an even distribution. Histograms are for columns that are skewed and not…