On rare occasions, an application may spawn errors similar to the below:
com.google.appengine.api.datastore.DatastoreFailureException:
internal error.
at com.google.appengine.api.datastore.DatastoreApiHelper.translateError (DatastoreApiHelper.java:50)
at com.google.appengine.api.datastore.DatastoreApiHelper$1.convertException (DatastoreApiHelper.java:70)
As the exception message suggests, this log indicates that the datastore encountered an internal error while handling the datastore operation. Unfortunately, there’s nothing that a developer can do to fix this error since it’s an internal App Engine issue.
Generally this type of exception fixes itself sooner or later; if it persists, file an issue at the App Engine bug tracker: https://code.google.com/p/googleappengine/issues/entry?template=Production%20issue