A third of my request was the garbage collector

Fri, 09 Oct 2026 00:00:00 +0000

The rostering app I maintain has a grid that shows a whole organisation’s shifts for a quarter. On live it took 1.1 to 1.5 seconds to load, and the app logs anything over 500 ms as a slow grid, so I spent a morning on it. The obvious suspects were the obvious ones: queries, and the Python that turns rows into cells. Both were guilty. But after a first round of fixes to those, the biggest remaining cost was somewhere I’d never have looked.

Performance on Wilhelm Maritz

A third of my request was the garbage collector