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GAE (Google App Engine) + BigTable

From version 1.1.0 on, Cumulus4j works with Google's BigTable as underlying datastore. But you need datanucleus-appengine version 2.1.2-nl20121012 as well as DataNucleus 3.1.3. It does not work with the older versions currently still used by default in the GAE! We recommend that you check the pom.xml files of the org.cumulus4j.gae.test project group. This project group is an integration test run automatically in our Jenkins to ensure compatibility with the GAE.

However, BigTable-support is still experimental! There are known problems when using transactions, because GAE does not allow more than 5 entity groups to be touched within a single transaction. Due to the architecture of Cumulus4j, these 5 entity groups are already reached when persisting a single object with 4 indexed (queryable) fields.

If you intend to use Cumulus4j in the GAE, we therefore recommend to use Google Cloud SQL as a short-term-solution.

Note, that the key management still needs to be done manually by your application code (no matter whether using BigTable or Cloud-SQL), but we plan to provide libraries for GWT in one of the next versions. You're very welcome to contribute!

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