Storing large blob with Objectify Appengine

Question

I have this class which I want to persist using Objectify, this class will represent a data larger than 1MB so there's a List of Blob objects which represents a fragment of the byte array stored that is less than 1MB in size:

@Entity
public class BigBlob {

    @Id
    private Long id;
    public static final int FRAGMENT_LIMIT = 777 * 1024;
    @Serialized
    private List<Blob> fragments = new ArrayList<Blob>();

    ...

}

Yet, the the "fragments" is @Serialized, which will render the size of this BigBlob class/object larger than 1MB.

Causing this error:

com.google.apphosting.api.ApiProxy$RequestTooLargeException: The request to API call datastore_v3.Put() was too large.

If I use @Embedded annotation I get this error:

Cannot place array or collection properties inside @Embedded arrays or collections

How do I make sure that the "fragments" are stored as a separate entity?

BTW, I already have the byte chunking logic that chops the whole byte array and put the fragments into a List of Blob so this question does not pertain as to how to chop bytes.

Mostly what I want to know is more on the persisting side.

Answer 1

You should store it in the Blobstore and just save the Blobkey in Objectify. Objectify works on top of the datastore, not the blobstore.