Hey Steve, Notes inline.
On Wed, Mar 2, 2011 at 18:03, stevep <[email protected]> wrote: > I am right in understanding HR performance? If my code executes: > > entity = myRecs.get_by_key_name(myKey) > entity.counter += 1 > entity.put() You're doing this inside a transaction, right? :) > > This code will: > 1) Take 2x as long in HR vs. MS >From some of the graphs / numbers posted recently and based on my experiments, I'm not sure it will actually take 2x as long in practice (but it maybe a good safety assumption). If you hit a latency spike in the M/S, I'm sure HR won't take 2x as long. :) > 2) Should not be execute more than once per second Yeah, ballpark something around 1 or 2 times per second. > > For item 1: If MasterSlave latency is 100 ms, > this should be expected to take 200 ms in HR. > > Item 2: Do not repeat this code for the selected > entity more than once per second, but ok to > execute for other entities within that one second > (different myKey values -- up to 5 different entities > updated in a second if the sole latency was the 200ms). Yep, you can run this across multiple entity groups. Robert > > Many Thanks, > stevep > > On Mar 2, 9:59 am, Robert Kluin <[email protected]> wrote: >> HR does have a slightly higher latency which would reduce the rate a >> little, but 1/second is to leave a safety margin. In practice you'll >> probably be able to get more, but you should not design an app >> assuming you'll be able to sustain 5 writes to an entity group per >> second. >> >> Robert >> >> >> >> On Wed, Mar 2, 2011 at 11:43, Spines <[email protected]> wrote: >> > The using the HR datastore page (http://code.google.com/appengine/docs/ >> > python/datastore/hr/overview.html) says: >> >> > "This allows queries on a single guestbook to be strongly consistent, >> > but also limits changes to the guestbook to 1 write per second (the >> > supported limit for entity groups)". >> >> > I remember reading a while ago (before the HR datastore existed) that >> > you could get about 1 to 5 writes per second to an entity group. >> >> > Is the supported writes per second to an entity group less on the HR >> > datastore? >> >> > -- >> > 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 >> > athttp://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. > > -- 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.
