Hello! Baloo (more specifically baloo_file_extractor) has a very high CPU usage when some new folder with large (or not so large) amount of contents has been recently created. Typical example is extracting archives - I've had this problem when extracted icon theme from archive. openSUSE Leap 42.2/42.3 with Plasma 5.8 LTS
High CPU also exists in Plasma 5.12 LTS/Leap 15/XFS file system, especially on reindexing/recreating the database.
This should be fixed now.