[phamilton]

I've wondered similarly. I don't have answers for you, but to add more questions: Are there tree structures that are more amenable to SSDs and the associated write amplification and other perf penalties? Could "hard-linking" in the SSD facilitate covered indexes? Could bitwise operations be performed on the SSD itself?

Edit: I found some exploration: https://www.usenix.org/conference/osdi14/technical-sessions/...

[j-pb]

We're doing just that. We have an index trie datastructure that is optimized for manipulation by an FPGA in an SSD.

Xillinx recently released a product that enables this which it's super awesome and even affordable.

https://www.xilinx.com/applications/data-center/computationa...

[infogulch]

Very cool! It seems to me that the "disk as a contiguous array of blocks"-paradigm is simply unsuited to SSDs, and ssds have to do a lot of work to support that fiction for the OS and databases in particular. If that's a reasonable assessment, then the next question is: what is a better model/paradigm for cell storage that minimizes bookkeeping overhead?