SQLite3 is not a high-write-concurrency database, but not a high-throughput DB is less clear, and it's not at all clear that it can't be hacked on to go faster.

SQLite3 is not a high-write-concurrency database, but not a high-throughput DB is less clear, and it's not at all clear that it can't be hacked on to go faster. If you take a sharding approach to concurrency, you might just be happy with no write concurrency: one process/thread per-CPU / storage slice, and fix everything else upstairs. It's not a crazy approach, and it might be the approach many would take if they could start from scratch. In fact, it's the approach Spanner takes, for example.