These are the stats from the database in question…
The smart rule is an AppleScript a few thousand lines long so not really worth sharing but it does update a lot of custom data fields. I regularly see Devonthink running flat-out at 99% busy. As well as smart rules taking longer to run with if the smart rule is open,
Maybe when I can switch to “matches” rather than “is” as per this thread maybe performance will improve overall as even the smart rule view can take 15-30 seconds to populate even before the smart rule runs.