Why are LSM trees called index structure? My understanding is that they are a "storage technique" i.e., how you store the data underneath.
In fact, for performance reasons you would need an index on top of this data --in this case of LSM an in-memory hash map or a block index - to quickly locate the data you want.
I understand that you can store the index content as LSM tree internally but almost everywhere I've read LSM tree being referred as indexing structure. I find this confusing and doubt if I've got the concept right?
Thanks