An app instance cannot serve 2 request at the same time. Suppose you have 100 requests/sec, and GAE offers 100 app instances to serve these requests. At one time it suddenly raise up to 200 requests/sec, so GAE tries to create 100 more app instances to serve. But create a new Java instance may need more than 5 seconds, in these 5 seconds, 500 requests have to wait, and new requests are still coming. So GAE create even more app instances, maybe 50, 100 or 200, and kill them when the 500 requests have been finished. Thus I think Java will waste much more time than Python.
Query between Python and Java is almost the same speed, but you need low-level api for batch query: http://gaejava.appspot.com/ 2009/11/29 Eric <[email protected]>: > Another question, you both recommended Python for some of its > features, but isn't Python much slower than Java? So wouldn't that > necessitate many more instances/CPUs to keep with the query load? > > On Nov 28, 9:45 am, Niklas Rosencrantz <[email protected]> wrote: >> >> 1) pricing >> >> absolutely seems so. gae apps 1/20 cheaper than previous >> hostingmethods (servers)>> 2) latency resulting from slow CPU, JIT compiles, >> etc. >> >> latency oriented group we don't focus >> onhttp://groups.google.com/group/make-the-web-faster >> in the long run, yes. you can compare to dedicated physical server, >> much more difficult to configure, compile modules spec for physical >> architecture, get superiour response time with C++ server pages ouput >> "hello world" while best project is security and convenience are >> kings. latency least prio still important. >> >> python is good, same thing in python 1/10 code compared to java, no >> XML, yaml very neat. java strong point: more ways to solve same >> problem. >> >> On Sat, Nov 28, 2009 at 6:35 AM, 风笑雪 <[email protected]> wrote: >> > The White House hosted an online town hall meeting on GAE with GWT, >> > and received 700 hits per second at its peak. >> >http://google-code-updates.blogspot.com/2009/04/google-developer-prod... >> >> > But more than 1000 queries a second is never been tested. >> >> > I think Java is not a good choice in your case. When your user >> > suddenly increasing, starting a new Jave instance may cost more than 5 >> > seconds, while Python needs less than 1 second. >> >> > 2009/11/27 Eric <[email protected]>: >> >> >> Hi, >> >> >> I wish to set up a CPU-intensive time-important query service for >> >> users on the internet. >> >> Is GAE with Java the right choice? (as compared to other clouds, or >> >> non-cloud architecture) >> >> Specifically, in terms of: >> >> 1) pricing >> >> 2) latency resulting from slow CPU, JIT compiles, etc.. >> >> 3) latency resulting from communication of processes inside the cloud >> >> (e.g. a queuing process and a calculation process) >> >> 4) latency of communication between cloud and end user >> >> >> A usage scenario I am expecting is: >> >> - a typical user sends a query (XML of size around 1K) once every 30 >> >> seconds on average, >> >> - Each query requires a numerical computation of average time 0.2 sec >> >> and max time 1 sec (on a 1 GHz Pentium). The computation requires no >> >> data other than the query itself. >> >> - The delay a user experiences between sending a query and receiving a >> >> response should be on average no more than 2 seconds and in general no >> >> more than 5 seconds. >> >> - A background save to a DB of the response should occur (not time >> >> critical) >> >> - There can be up to 30000 simultaneous users - i.e., on average 1000 >> >> queries a second, each requiring an average 0.2 sec calculation, so >> >> that would necessitate around 200 CPUs. >> >> >> Is this feasible on GAE Java? >> >> If so, where can I learn about the correct design methodology for such >> >> a project on GAE? >> >> >> If this is the wrong forum to ask this, I'd appreciate redirection. >> >> >> Thanks, >> >> >> Eric >> >> >> -- >> >> >> 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 >> > 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.
