Stefan, Keep on the lookout for a Google IO talk, "Scaling App Engine apps" that Guido and Justin did this year at Google IO. There's a bit in there about how we decide to dynamically add instances.
Ikai Lan Developer Programs Engineer, Google App Engine Blog: http://googleappengine.blogspot.com Twitter: http://twitter.com/app_engine Reddit: http://www.reddit.com/r/appengine On Wed, May 11, 2011 at 12:33 PM, Stefan Podkowinski < s.podkowin...@gmail.com> wrote: > I never really cared much about instances as I don't have much influence on > how they are created and torn down anyways. But maybe someone can shed some > light on how the scheduler works as of today. Lets take a look at the > following example that I just took from my apps admin console. > > QPS* Latency* Requests Errors Age Memory Availability > 1.300 29.4 ms 575 0 0:07:20 66.7 MBytes Dynamic > 2.667 28.7 ms 5238 0 0:49:13 108.9 MBytes Dynamic > 0.617 31.9 ms 4988 0 0:49:11 109.9 MBytes Dynamic > 0.333 57.6 ms 4342 0 0:46:08 109.1 MBytes Dynamic > 0.000 0.0 ms 25 0 0:07:26 65.5 MBytes Dynamic > 0.000 0.0 ms 2 0 0:06:39 65.1 MBytes Dynamic > > My python application is serving a lot of very low latency requests that > usually involve just 2-3 datastore or memcache read operations. If I > understand the numbers correctly it takes about 30-60ms to create a response > for each request, but only up to 0.3-2.6 QPS are served from multiple > instances. How does this make any sense? > > If Google is really going to change "fix" the scheduler I'm wondering why > this hasn't happend before the new pricing model announcement, so Google > itself would get some hard numbers first for building a new pricing > parameters? > > Also, how can Google make sure that unresponsive instances are due to bad > coding practices instead of just broken nodes? I mean I don't care that much > if some datastore operations fail to execute to whatever reason as they can > simply be re-executed from another task. But getting billed for instances > that might be slow due to infrastructure issues, thats not acceptable. > > > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine" group. > To post to this group, send email to google-appengine@googlegroups.com. > To unsubscribe from this group, send email to > google-appengine+unsubscr...@googlegroups.com. > 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 google-appengine@googlegroups.com. To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
