> but it would be awesome to see a PostgreSQL compatible frontend

Why not just use PostgreSQL directly?

Aurora has a bunch of nice features WRT automatic failover, redundancy, and automatically scaling storage as you push more data into the DB.

Does Aurora do anything other than detect a heartbeat failure, shoot the node in the head and bring it up on another box WRT failover?

That is the basic idea on such things, though distributed protocols become complex when you have to consider split-brain, multiple concurrent failures, etc which all can occur in large-scale events.

Aurora leverages Amazon RDS Multi-AZ in this area. Their implementation has been battle-tested over many years and many many db instances.

I'm really wondering if something very close will be possible soon with AWS EFS.

A Postgres to MySQL client mapping middleware is probably the holy grail? I think it's been done in the JDBC space.

You can get this essentially via mysql_fdw: https://github.com/EnterpriseDB/mysql_fdw

Oh yes, please.

That would greatly simplify tooling and integration with RedShift (which already uses PostgreSQL frontend/protocol).

If you want to synchronize your postgres db (and a lot of other things) to redshift, we do it as a service at fivetran.com

There's no such concept of Storage Engines/Plugins in PostgreSQL. So it looks more unlikely this could happen in short time.

Yes, there are:

http://www.postgresql.org/docs/9.4/static/extend-extensions....

https://wiki.postgresql.org/wiki/Foreign_data_wrappers

Isn't Aurora simply Amazon's private fork of MySQL, hosted for you?

The already have that in RDS. This is a da add of their own design. They were pragmatic enough to use the query language that most devs already know and trust, but how they pull off reads, writes, and sharing at that scale must have fundamentally different internals than a single MySQL instance.

It certainly seems to be a MySQL 5.6 fork (or at least backend ala InnoDB or similar), as the docs explicitly call out MySQL 5.6 compatibility. I feel like I wouldn't say "simply" though; that makes it seem like some guys at Amazon checked out the MySQL source, deleted some stuff and then released this.

Unlikely, because they already have a hosted MySQL 5.6 product in RDS. If anything, this is a MySQL 5.6 frontend + query processing engine with a new storage layer.

It would have been extremely difficult because MySQL community edition is GPL and Amazon does not allow GPL code to be modified by the internal teams as far as I know. They might have changed their policy though...