BTW: What's your take on random read speed? I think with SSDs now and maybe NVRAM in the future we can address physical storage more fine granular than with HDDs and for instance with http://sirix.io data is only clustered during writes (batched and synced to the flash drive) and it versions variable length in-memory and physical pages such that not every record has to be copied and written again. For instance to reconstruct a page we have to read from random places (maybe in parallel) to reconstruct a page in-memory. Thus Sirix relies on fast random read speed and on find granular access to the physical stored records.