Video
Production Is Live, the Boards Aren't
The boards on five production lines fall behind the floor on a busy shift. The screens aren't at fault — a single query that converts dates is.
The factory runs five production lines; the board at the end of each one shows today's count. It has worked that way for years — until, on a busy shift, production manager Serkan notices the board and the floor no longer agree.
Data lead Zeynep finds the fault isn't in the screens: the query that counts daily production converts every stored date while comparing. The database can't use the existing index and reads millions of rows end to end — CPU sits in the 90s, and a single number takes eight seconds.
Once the traffic runs through Quentra, the query is rewritten in flight: the conversion goes, replaced by a date range the index can read. The query drops to milliseconds and the five boards flip back to live, one after another. Not a single line of application code changes.