I have a decent sized database on Google App Engine and I am using the current Datastore as well as the Blobstore for photos. I am just curious about the advantages and then difficulties in transitioning to the Google Cloud SQL.
Google says that it is faster for reads and writes but doesn't say how it compares on cost. Also is either one more scalable? Right now everything is working well on the HRD but I am wondering if it will be worth it down the road to transition to GC SQL.
You might find this presentation from Google I/O informative: SQL vs NoSQL: Battle of the Backends. Spoiler: Datastore is more scalable, but Cloud SQL is better for apps that don't need scalability.