On Tuesday, 12 June 2012 06:20:08 UTC+7, Jeff Schnitzer wrote: > > Ah, sorry that wasn't clear to me. > > I'm not sure how the presence of Objectify in this chain could make > any difference. There's nothing special about the way Objectify > starts or commits a transaction. Was this behavior consistent? > > Jeff > > On Mon, Jun 11, 2012 at 8:00 AM, Michael Hermus > <[email protected]> wrote: > > Jeff, > > > > There are absolutely no entities being modified or created, so there is > no > > possibility of data store contention (based on my current > understanding), > > hence the topic. The only operations during the transaction are Task > Queue > > inserts. As I said, there is really no reason to use Objectify under > those > > circumstances so its not really a problem, just something to be aware > of. > > > > Regards, > > Mike > > > > On Sunday, June 10, 2012 11:46:24 PM UTC-4, Jeff Schnitzer wrote: > >> > >> ConcurentModifcationException happens whenever you have transaction > >> collisions. You will often have transaction collisions if you modify > >> the same piece of data from multiple tasks. > >> > >> There are two possible situations here: > >> > >> 1) "It happens" - sometimes transactions collide. The solution is > >> that you should always make transactions idempotent and you should > >> always retry them. If you're using Objectify4, doing an > >> ofy.transact(new Work() { ... }) will do the retries for you. > >> > >> 2) You may need to rethink the way data flows in your app. If you > >> have a bunch of tasks trying to modify the same piece of data, you're > >> going to get a lot of collisions and collisions slow things down. > >> Figure out how you can serialize the transactions or combine them. > >> > >> Jeff > >> > > -- > > You received this message because you are subscribed to the Google > Groups > > "Google App Engine" group. > > To view this discussion on the web visit > > https://groups.google.com/d/msg/google-appengine/-/YEVYcmRii_gJ. > > > > 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. >
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