It looks like the next big step will be comming soon. On the main branch we have now the memtable. Again do not use it. There is still ongoing work.
The problem with memtable and hashtable on SSD is the question how to rebuild the hashtable. We did some benchmark tests and it would take days for a full drive. For the memtable it would have to run that on every reboot. So we need a fast rebuild otherwise we can’t use memtable.
Solution: Write a small hint file side by side with the log file. That way rebuilding the hashtable will be a lot cheaper. So thats the next steps that will get implemented.
In the meantime I have to repeat it one more time. Please do not move your hashtable to SSD or memtable. Let the developer trigger all the landmines first.