The 1M "TPS" you're referring to is a read-only benchmark (e.g. http://akorotkov.github.io/blog/2016/05/09/scalability-towar...). Those are reads (most likely from the buffer cache), not writes or transactions in any real sense.

We should track disk IOPS, though, so you can do an apples-to-apples comparison of how much low-level throughput the database is driving. I believe the instance store disks in the EC2 C3 hardware class can support about ~20K write IOPS each.

On the other hand, the Fauna numbers don't seem that impressive to me. On a mid-2011 Macbook Air, I get 2600 transactions per second (read-committed) in PostgreSQL 9.6. Setup is as follows:

  CREATE TABLE IF NOT EXISTS foo(a TEXT, b TEXT, c TEXT, d TEXT);
  CREATE INDEX IF NOT EXISTS idx_foo_a ON foo(a);
  CREATE INDEX IF NOT EXISTS idx_foo_b ON foo(b);
  CREATE INDEX IF NOT EXISTS idx_foo_c ON foo(c);
  CREATE INDEX IF NOT EXISTS idx_foo_d ON foo(d);

  -- prepared statement, the inserted strings are 4 chars wide
  INSERT INTO foo(a, b, c, d)
  VALUES
    ($1, $2, $3, $4),
    ($5, $6, $7, $8),
    ($9, $10, $11, $12),
    ($13, $14, $15, $16);

Am I missing something?

Additionally you have the bottleneck of a single master. Will it be possible to do a quorum read as well, and will every transaction on the master be doing it? Then you are starting to get closer, although many anomalies are still possible.

If you ran the benchmark yourself, how did you achieve 1m durable writes/sec on a postgres machine/instance? [It's quite an achievement] On what kind of crazy hardware? How large was each write/row? Did you use the postgres network protocol to perform the writes?