> If you build a custom database
> engine that fundamentally stores
> everything as key-value, and then
> builds relational abstractions on
> top
More like myRocks. FoundationDB doesn't use LSM and definitely wants to do lots of overwriting in place. TiDB uses Rocksdb and would be closer.
Completely agree. There is another angle you can play if you are willing to get your hands dirty at the lowest levels.
If you build a custom database engine that fundamentally stores everything as key-value, and then builds relational abstractions on top, you can leverage a lot more benefit on a per-transaction basis. For instance, if you are storing a KVP per column in a table and the table has 10 columns, you may wind up generating 10-20 KVP items per logical row insert/update/delete. And if you are careful, you can make sure this extra data structure expressiveness does not cause write amplification (single writer serializes and batches all transactions).