Debugging a slow photo library

Naming things clearly helped more than any clever trick. I ran into this again last week, so here is a short note for future me.

The fix turned out to be one line, after an hour of looking in the wrong place. Writing a tiny test first made the problem obvious. Measuring before changing anything saved me from a pointless rewrite. Most of the time the simplest tool is good enough.

Next time I will start with the boring solution and see if it is enough. There is probably a better way, but this one is easy to remember. I wish someone had told me this when I started.