javax.persistence.PersistenceException: Transaction failed to flush

Question

I got the JPA exception

"javax.persistence.PersistenceException: Transaction failed to flush"

Then I deleted my local datastore(datastore-indexes-auto.xml and local_db.bin) from my system. Recreated all the data again and after that, the exception was gone. I want to know what did just happened ?

The following is the stacktrace

[RPC Fault faultString="org.springframework.orm.jpa.JpaSystemException : Transaction failed to flush; nested exception is javax.persistence.PersistenceException: Transaction failed to flush" faultCode="Server.Processing" faultDetail="null"]
at mx.rpc::AbstractInvoker/http://www.adobe.com/2006/flex/mx/internal::faultHandler()[C:\autobuild\3.5.0\frameworks\projects\rpc\src\mx\rpc\AbstractInvoker.as:290]
at mx.rpc::Responder/fault()[C:\autobuild\3.5.0\frameworks\projects\rpc\src\mx\rpc\Responder.as:58]
at mx.rpc::AsyncRequest/fault()[C:\autobuild\3.5.0\frameworks\projects\rpc\src\mx\rpc\AsyncRequest.as:103]
at NetConnectionMessageResponder/statusHandler()[C:\autobuild\3.5.0\frameworks\projects\rpc\src\mx\messaging\channels\NetConnectionChannel.as:581]
at mx.messaging::MessageResponder/status()[C:\autobuild\3.5.0\frameworks\projects\rpc\src\mx\messaging\MessageResponder.as:222]

Answer 1

I don't know google-app-engine, but I assume you have some limited space in DB there? Maybe you just run out of space?