Apple - How to disable Spotlight and mds_stores on Mac OS Catalina
In my experience, a failing disk and/or a disk filesystem that’s damaged or failing is the cause for most spotlight processes that run too long. Also, metadata importers that are added by programs like Office and others run to index their files and can cause issues.
Before you disable this entirely, have you opened the spotlight settings and added each user home folder to the privacy? This cleans all records of those user files from the database. Then you would restart the machine and perhaps boot to recovery HD and run Disk Utility to repair the disk.
Sometimes a clean install is all that’s needed - https://apple.stackexchange.com/a/66690/5472
Clearly, spotlight needs to take one pass over all the data, but then it should quit. As you say, if you don’t need it, adding the folders you wish to not have indexed is the easy way to let the system index things it needs, but ignore your user files, database files and other things that might cause temporary or permanent resource usage. I could see some high transaction data based never getting indexed if they don’t tell spotlight to not index files.
- Preventing Spotlight from Indexing Files & Folders?
My mds_stores, kernel_task, corespotlightd and other processes related to spotlight, have written and read over 10tb on my ssd in couple of days. After tried all solutions I could find on internet, I finally solved it by dragging my user folder into privacy list of Spotlight. I have no idea what happened and what caused it. But this madness reduced my ssd life to 47% from nearly full. Guess that's why you need to buy apple care.