title: NDB JsonProperty quota impact compared to old datastore properties?
body: <p>I seem to remember the old datastore properties have something like 2 <strong>datastore write operations</strong> (DWOs) per storage, and perhaps a few more depending on how they are indexed.</p>
  
  <p>In the old datastore, I would frequently store everything I didn't need to index in a JSON string and store that as a TextProperty to save on multiples of writes.</p>
  
  <p>Having gotten used to saving and working with everything in JSON straight from the datastore, when switching to the NDB for a new app, I naturally used the NDB JsonProperty. </p>
  
  <p>As is usual, I became paranoid about optimization the first time I checked out my quota limits (quintessential free-quota-limit user experience ?), and noticed all the datastore writes (which consisted entirely of models with only JsonProperties) were clocking up a lot of DWO quota. </p>
  
  <p>Immediately I wondered : Does GAE DataStore make multiples of writes depending on the structure of the JsonProperty? Or does it just store the whole property blob to the datastore in as few DWOs as are required for a "blob" store? </p>
  
  <p>I thought the latter, and remembered reading so in the docs, but the massive quota consumption (quintessential free-quota-limit user paranoia ?), made me wonder if maybe using JsonProperty was not as efficient as using the old datastore and saving the JSON strings as TextProperty -- which are certainly unstructured blobs. </p>
  
  <p>It would be good if this could be cleared up definitively, so I can get back to the "appengine promise" of focussing <em>only on the app.</em> :)</p>