I have table with index in reverse order (primary key(col DESC)). If I run myisampack, it generates 1kb file which doesn’t work. myisamchk rebuilds the index, and rebuilt index file has sensible size, but still doesn’t work – all I get is “126 Incorrect key file for table”.

I understand this is an old post, but it’s still very helpful.
However, one thing got me a bit puzzled: I’ve read & heard numerous times that mysql wouldn’t use indices for queries with LIKE ‘%abc%’ condition, which sort of made sense as it couldn’t go down the btree without knowing the first character… and indeed, whenever I tested it (with explain), it wouldn’t. But you suggest it does use index for you in this case? What’s the catch, am I missing something here?