Metadata writeback - how many processors?

[Aubrey]

I am writing back metadata. On interrogating the task manager, I find 6 sessions of exif tool running.
As I have 16 processors it it possible to have more exiftool sessions running so as to complete the task faster?

Thanks,
Aubrey.

[Mario]

The task is mostly I/O bound (disk input/output). Throwing more processors at it won't help. IMatch balances this automatically.

There is a lot gong on when IMatch is writing back data, and running multiple ExifTool instances at the same time, with potential overlapping writes when versions are involved and need to be updated, sidecar files are involved, parallel read-imports of the files running etc. Adding more ExifTool instances running in parallel won't improve performance at all, or even produce worse performance.

This is the reason why IMatch gives you options to override the default 'auto' parallelism used for file and metadata import, but not for metadata write-back.