The log caching feature is really nice for speeding up the display of large logs. However, it doesn't appear to cache merge commit messages.
I looked in Settings -> Log Caching -> Cached Repositories and confirmed that my repository is listed as being cached, but if I use the "Export" button on that page the "prefix.merges.csv" which is created has only a header row and no data. The other cache exports appear normal. This (that the merge export is empty) is the case for every repo I've tried.
Apologies, I wrote this up as a feature request but it may be more properly a bug, or it might be an issue with one of my settings.
Cheers,
T