Gregory, Thanks for the update. I think the scheduler min & max pending latency should be per url (i.e. in app.yaml) rather than being global at the app level. Most apps have requests that require a quick response (UI and APIs), and others that don't (cron, some tasks, backend work, ..etc). I'd probably want to set my max pending latency to 50ms for UI requests and 5 seconds for some non-urgent tasks.
Waleed On Fri, Jun 24, 2011 at 4:04 PM, Jeff Schnitzer <[email protected]> wrote: > 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. > -- 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.
