Sorry it was added in 12.12.2, not .3.
Added a simple caching system to the metadata thread so that multiple queries for the same file in a short space of time will come out of the cache rather than re-reading the file every time. Should improve performance when the file display is showing metadata columns and label filters are also querying metadata.
It was added to address this issue: Label filter by "Movies" category columns - #3 by bytespiller