LOAD INDEX INTO CACHE

MySQL & MariaDB Other MySQL® Questions
1

I have an index file with 3 indexes that does not fit into memory. So I tried loading just 1 index that would fit into memory.

LOAD INDEX INTO CACHE myTable (idx_1)

However I still see physical key reads going on for queries that use only that index. If I create the table with just the 1 index then I can load the index and get no physical key reads on queries. Am I doing something wrong or is this a bug?