Hie Ok thanks.. heard this word Objectify for the first time.... Not sure how much will be the efforts to migrate current jdo implementation to this. any advise ?
Thankx and Regards Vik Founder www.sakshum.com www.sakshum.blogspot.com On Mon, Oct 25, 2010 at 8:24 PM, Didier Durand <[email protected]>wrote: > Hi Vik, > > To be fully transparent, I stopped using JDO and switched to > Objectify: much more simple, efficient & transparent than JDO (just > check how many issues on this forum with jdo). Learning curve is very > quick. > > Wih Objectify, if your entities are not too big in size and well > indexed to match your queries, you can hope for many tenths of task > start (each with its own donor to process) in the course of 30s. I am > probably conservative. > > The advantage of starting additional tasks via API is parallelism: all > your donors will be processed simultaneously and then update job is > gonna be finished much faster overall. Be careful though if you have > global counters updated by many tasks in parallel: you may enter > concurrency race issues. But you can post again by then if needed to > solve those new issues... > > regards > didier > > On Oct 25, 2:45 pm, Vik <[email protected]> wrote: > > Hie > > > > thanks a lot!!! > > > > So, how about starting a corn job every day say at 00:00 and if time > > consumption goes more than 30 sec than scheduling tasks to complete > > leftovers. > > > > I have another question here: The data model for this is: > > > > BloodDonor_name, blood_group, is_active, active_date > > > > so query to find donors to be activated ids gonna be: > > > > select BloodDonor where is_active == false && active_date == <today's > > date> > > > > and update gonna be setting such donors: is_active=true and active_date > = > > null. > > > > Any idea how many such entries is safe to consider will be processed > within > > 30 secs ? > > > > Thankx and Regards > > > > Vik > > Founderwww.sakshum.comwww.sakshum.blogspot.com > > > > On Mon, Oct 25, 2010 at 5:53 PM, Didier Durand <[email protected] > >wrote: > > > > > Hi Vik, > > > > > I would also go with cron job in your case. > > > > > Concerning the 30s limit, it depends on your requirements in > > > computing: > > > > > a) you can and should probably schedule via api an independent task > > > for each separate donor who needs to be processed after your query > > > (via cron) told you who needs to be processed today. > > > > > b) then,for each individual task, if it lasts more than 30s then you > > > need to do what I described earlier (i.e pause the current run after > > > storing its context and restart it in a new task) > > > > > regards > > > didier > > > > > On Oct 25, 12:35 pm, Vik <[email protected]> wrote: > > > > Hie > > > > > > Hmm, so in my case I always know in advance that I need to activate > few > > > > blood donors every day which were deactivated yesterday. > > > > > > So, this qualifies for cron jobs. Isn't it ? However, does this 30s > limit > > > > applies here as well? > > > > > > Thankx and Regards > > > > > > Vik > > > > Founderwww.sakshum.comwww.sakshum.blogspot.com > > > > > > On Mon, Oct 25, 2010 at 11:56 AM, Didier Durand < > [email protected] > > > >wrote: > > > > > > > Hi, > > > > > > > I see different purposes for the 2: > > > > > > > - cron tasks are the tasks I always want to do for sure > > > > > - tasks via API are tasks that I schedule programmatically when > needed > > > > > and triggered by event that I can't predict in advance. > > > > > > > I see personally 2 other purposes for API tasks: > > > > > a) when I run a task and it comes close to the 30s limit, I pause > > > > > it, serialize its context and schedule a task with this context. > When > > > > > the task starts, it's in fact a restart with another 30s credit for > > > > > running > > > > > b) I also tasks in context of transactions if I want to be sure > that > > > > > the action of the task is done (i.e datastore writes) even if the > > > > > transactions fails -> for example, store errors in datastore for > > > > > later analysis for a failing transaction / program, etc. > > > > > > > regards > > > > > didier > > > > > > > On Oct 25, 6:23 am, Vik <[email protected]> wrote: > > > > > > Hie Thanks for the response. > > > > > > > > I am confused a bit. If cron job does the scheduling then what > Task > > > Queue > > > > > > does? > > > > > > > > Thankx and Regards > > > > > > > > Vik > > > > > > Founderwww.sakshum.comwww.sakshum.blogspot.com > > > > > > > > On Mon, Oct 25, 2010 at 8:51 AM, Didier Durand < > > > [email protected] > > > > > >wrote: > > > > > > > > > Hi Vik, > > > > > > > > > Tasks scheduled via cron.xml is the way I would go: > > > > > > >http://code.google.com/appengine/docs/java/config/cron.html > > > > > > > > > I would schedule a task every minute, make a query on the > deadline > > > for > > > > > > > donors and then do what has to be done. > > > > > > > > > didier > > > > > > > > > On Oct 24, 7:11 pm, Vik <[email protected]> wrote: > > > > > > > > Hie Guys > > > > > > > > > > Our application manages a list of blood donors. Time to time > > > these > > > > > blood > > > > > > > > donors are unreachable so the administrators can mark such > blood > > > > > donors > > > > > > > as > > > > > > > > inactive. > > > > > > > > > > However, these blood donors should be active again after 1 > day > > > > > > > > automatically. How should we achieve this? ?In regular J2EE > apis > > > we > > > > > can > > > > > > > > write scheduler classes to do the same. > > > > > > > > What is the option in GAE? Are there any limitations? > > > > > > > > > > I went through a bit and feel like task queues are the way. > But I > > > am > > > > > not > > > > > > > > sure? If yes then for above scenario how should it be done? > > > > > > > > > > Thankx and Regards > > > > > > > > > > Vik > > > > > > > > Founderwww.sakshum.comwww.sakshum.blogspot.com > > > > > > > > > -- > > > > > > > You received this message because you are subscribed to the > Google > > > > > Groups > > > > > > > "Google App Engine for Java" group. > > > > > > > To post to this group, send email to > > > > > > > [email protected]. > > > > > > > To unsubscribe from this group, send email to > > > > > > > [email protected]<google-appengine-java%[email protected]> > <google-appengine-java%[email protected]<google-appengine-java%[email protected]> > > > > > <google-appengine-java%[email protected]<google-appengine-java%[email protected]> > <google-appengine-java%[email protected]<google-appengine-java%[email protected]> > > > > > > > > > <google-appengine-java%[email protected]<google-appengine-java%[email protected]> > <google-appengine-java%[email protected]<google-appengine-java%[email protected]> > > > > > <google-appengine-java%[email protected]<google-appengine-java%[email protected]> > <google-appengine-java%[email protected]<google-appengine-java%[email protected]> > > > > > > > > > > > . > > > > > > > For more options, visit this group at > > > > > > >http://groups.google.com/group/google-appengine-java?hl=en. > > > > > > > -- > > > > > You received this message because you are subscribed to the Google > > > Groups > > > > > "Google App Engine for Java" group. > > > > > To post to this group, send email to > > > > > [email protected]. > > > > > To unsubscribe from this group, send email to > > > > > [email protected]<google-appengine-java%[email protected]> > <google-appengine-java%[email protected]<google-appengine-java%[email protected]> > > > > > <google-appengine-java%[email protected]<google-appengine-java%[email protected]> > <google-appengine-java%[email protected]<google-appengine-java%[email protected]> > > > > > > > > > . > > > > > For more options, visit this group at > > > > >http://groups.google.com/group/google-appengine-java?hl=en. > > > > > -- > > > You received this message because you are subscribed to the Google > Groups > > > "Google App Engine for Java" group. > > > To post to this group, send email to > > > [email protected]. > > > To unsubscribe from this group, send email to > > > [email protected]<google-appengine-java%[email protected]> > <google-appengine-java%[email protected]<google-appengine-java%[email protected]> > > > > > . > > > For more options, visit this group at > > >http://groups.google.com/group/google-appengine-java?hl=en. > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine for Java" group. > To post to this group, send email to > [email protected]. > To unsubscribe from this group, send email to > [email protected]<google-appengine-java%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/google-appengine-java?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Google App Engine for Java" group. 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