Thanks, this clarifies much! Questions below: On Thu, Jun 23, 2011 at 11:49 PM, Gregory D'alesandre <[email protected]>wrote:
> Datastore APIs Q: Which operations are being charged for? > A: There are 3 categories of Datastore operations: > - Write operations (Entity Put, Entity Delete, Index Write), each of these > operations will cost $0.10 per 100k operations > - Read operations (Query, Entity Fetch), each of these operations will cost > $0.07 per 100k operations > - Small operations (Key Fetch, Id Allocation), each of these operations > will cost $0.01 per 100k operations > > Q: Under the new scheme, is it more economical to do a keys-only query that > fetches 1000 keys, and then do a get on the 500 of them that I need, or just > do a regular (non keys-only) query for all 1000 directly? > A: The first is more economical. Fetching 1000 keys + fetching 500 > entities = $0.0001 + 0.00035 = $0.00045; fetching 1000 entities = $0.0007. > This makes sense, and encourages more use of memcache. to hold entities. One question that I've been wondering a while - presuming no caching, does this query-keys+batch-get approach produce higher latency than a simple query, and if so, by how much? Also, is there any way we can get the transaction timestamp out on datastore writes? This would *dramatically* improve the robustness of code that tries to keep memcache in sync with the datastore during contention. I've spoken with Alfred and Max about this, but I don't know if it's a priority. This could potentially reduce datastore bills by orders of magnitude. Thanks, Jeff -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
