Improve App Engine performance by reducing entity size

Question

The objective is to reduce the CPU cost and response time for a piece of code that runs very often and must db.get() several hundred keys each time.

Does this even work

Answer 1

To answer your questions in order:

• Yes, splitting up your model will reduce the fetch time, though probably not linearly. For a relatively small model like yours, the differences may not be huge. Large list properties are the leading cause of increased fetch time.
• Old properties will still be transferred when you fetch an entity after the change to the model, because the datastore has no knowledge of models.
• Also, however, deleted properties will still be stored even once you call .put(). Currently, there's two ways to eliminate the old properties: Replace all the existing entities with new ones, or use the lower-level api.datastore interface, which is dict-like and makes it easy to delete keys.