Mastering Google App Engine

Blobs

While discussing datastore, we mentioned that you can store binary objects in ndb.BlobProperty, but there's a better way to do this. The ndb.BlobProperty directly stores uninterpreted bytes in datastore. One of the criteria for datastore pricing is the amount of data that goes out of datastore. So, if you have stored large blobs in datastore, it will become expensive while reading out your entities.

However, you can avoid this by using GQL (or projection via API) and only selecting a few properties, and this might save you some bandwidth. But the real problem still exists. You may recall that all the entity properties are stored in a single column in the underlying BigTable. So, even if you select only a few properties, this might save you ...