Hacker News Reader

It doesn't. It's not a hash, it's the actual key.

Yep.

For this case, conflicts can be solved via the traditional separate chaining strategy, to open a list on the Item.

This htree was originally implemented as the indexing container to store key-value poisition informations for the bitcask storage engine. And string keys are not stored in the htree to save more memory. Collisions of two string keys are distinguished by checking the disk.

And the origin string keys are stored in the htree item only if there is collision. So the string key distinguishing checks are at most once.

The Item interface requires a uint32 typed key, meaning that if you need a hash function to derive the key, you are responsible for resolving the collisions :D