If the parent is talking about the Windows search software Everything (https://www.voidtools.com/), it does index the files (but unsure of how, it's relatively quick compared to other Windows tools that does the same, so probably some magic involved?) at startup, then continuously indexes (as far as I can tell) but then after that the searches are instant.
> "Everything" only indexes file and folder names and generally takes a few seconds to build its database. A fresh install of Windows 10 (about 120,000 files) will take about 1 second to index. 1,000,000 files will take about 1 minute.
Re changes:
> Does "Everything" monitor file system changes?
> Yes, "Everything" does monitor your file systems for all changes. Your search results will update in real-time to reflect any changes. Everything will automatically keep your NTFS indexes up to date with the NTFS USN Journal. Changes will not be missed when Everything is not running as the system maintains the NTFS USN Journal.
Yes, exactly the principle as SwiftSearch - bypassing the slow fs and getting instant results (but ntfs only), and checking fs logs directly to keep track of all the updates
