
All that is old is young again.
Didn't ICL do a "Content Addressable Memory" disk drive back in the 70's?
AIUI it worked quite well within the limits of the technology in letting you pull big subsets of records off while ignoring the others on the disk, provided the DBMS could take advantage (which of course only ICL's system could).
So not a bad idea but very tricky to sell without the customers feeling a very strong sense of proprietary lock in, whatever the processor in the drive is.