> So, I finally decide to focus on the project idea of improving hash
> index now. It's more valuable , and also challenging.
>
> Any suggestion about the project idea of improving hash index?
Imho one thing to look into is the storage. I do not see any real value
in storing the key itself (especially longer keys) in the hash buckets.
Instead store the hash value only (or not even that) and mark the index
lossy (recheck the key in the heap).
Andreas