[wutwutwat]

They used their metrics to confirm the regression, and flame graphs to see where the cpu was spending its time. That’s performance tuning basics and anyone who is familiar with profiling code should be able to find the slow spots.

I’ve been doing Ruby for a decade and the matches? method immediately stood out to me. Methods doing any kind of comparison/regex or looping usually end up causing problems. Nokigiri was walking a tree of child nodes and doing a string comparison. I’ve seen people write themselves similar problems with methods like any? includes?, excludes?, etc. Par for the course.