Google App Engine to support SQL
groups.google.com
groups.google.com
The problems with app engine and the datastore have shown that there was a high level misunderstanding underlying the core design of the datastore... and how it would function in the context of lots of simultaneous users.
So I'd feel a lot more confident if Google addressed this concern other than with the high availability datastore...
With SQL on AppEngine, corporate developers can build apps like this without learning how to use NoSQL for persistence. Even if GAE's SQL doesn't allow scale-out sufficient for SaaS vendors and such, it will fill an important niche in Google's apparent goal of moving corps onto their cloud. As another commenter here suggested, the bar for perf/scale in many cases may be no higher than that provided by a MSAccess DB hosted on a Windows fileshare.
Luckily, it's an open standard (like email) and adding in support for an open, strongly-desired, useful stamdard as a feature should be applauded.
Scalable SQL is.
I think that the nonrel project has utility on other places (redis, mongo, etc...) but ABP (all buttons pressed, creators of nonrel) was pushing django on GAE alot, IIRC.
Truth be told however, Django and a SQL based system aren't all that bad.
No matter what, it will be a long time before Django gets full 1.0 support for NoSql in any shape or form. That means, 100% Django coverage.
I hear they've improved latency since I left, so take this with a grain of salt. I'm still not going back any time in the next few years, though.
I'm guessing that SQL is actually going to be more useful for anyone doing e-commerce (hence transactions) or anyone with familiarity with traditional SQL based persistence (even - shock horror - JDBC).
SQL is bland, BigTable is sexy. But another word for bland is mature...
I didn't remember seeing SQL on the roadmap however so I had another look ( http://code.google.com/appengine/docs/roadmap.html ) and I'm very excited to see it as been revised with a few awesome enhancements. I've had several projects I wanted to try on app engine which were impractical because of GAE limitations like no full text search, no programmatic access to blobstore, no bulk export/backup, no mapreduce. The future is looking a lot brighter for GAE.
Being able to use SQL on GAE will allow more widespread use of GAE for things besides "the next twitter".
The other limitations I listed didn't seem to have architectural causes so I find them more frustrating.