GAE DataStore vs Google Cloud SQL for Enterprise Management Systems

Question

I am building an application that is an enterprise management system using gae. I have built several applications using gae and the datastore, but never one that will requir

Answer 1

What is scare me more in GAE datastore is index number limitation. For example if you need search by some field or sorting - you need +1 index. Totally you can have 200 indexes. If you have entity with 10 searchable fields and you can sort by any field - there will be about 100 combunations. So you need 100 indexes. I have developed few small projects for gae - and this is success stories. But when big one come - this is not for gae.

About cache - you can do it with gae, but they distributed cache works very slow. I prefer to create private single instance of permanent backend with RESTfull API that holds cached values in memory. Frontend instances call this API to get/set values.

Maybe it is posible to build complex system with gae, but this will be a set of small applications/services.

Answer 2

From the Cloud SQL FAQ:

Should I use Google Cloud SQL or the App Engine Datastore?

This depends on the requirements of the application. Datastore provides NoSQL key-value > storage that is highly scalable, but does not support the complex queries offered by a SQL database. Cloud SQL supports complex queries and ACID transactions, but this means the database acts as a ‘fixed pipe’ and performance is less scalable. Many applications use both types of storage.

If you need a lot of writes (~XXX per/s) to db entity w/ distributed keys, that's where the Google App Engine datastore really shine.

If you need support for complex and random user crafted queries, that's where Google Cloud SQL is more convenient.