Hey, Vince, That's really cool. Does that address the need of the OP though? I may just not be understanding it fully ...
Thanks! On Aug 26, 11:15 am, Vince Bonfanti <[email protected]> wrote: > I've implemented a set of distributed locks for GAE that I posted a > message about previously (especially note the current limitations of > reliability of shared/read locks): > > http://groups.google.com/group/google-appengine-java/browse_thread/th... > > Here's a direct link to the source code: > > http://code.google.com/p/gaevfs/source/browse/trunk/src/com/newatlant... > > Since posting that message, I've done some timings on memcache calls > and found that they usually take about 15ms; I've seen low times > around 6-7ms and high times as much as 60ms. > > The ExclusiveLock is the most efficient, since it takes only one > memcache call to acquire and one to release. If you use the > ReadWriteLock class, it takes two memcache calls to acquire a write > lock, and three memcache calls to acquire a read lock (it only takes > one memcache call to release either a write or read lock). > > So, while using ReadWriteLock allows the greatest concurrency in your > application, unless the read operations take longer than 45ms on > average, you might be better off using ExclusiveLocks. > > Let me know if you find this useful. > > Vince > > On Wed, Aug 26, 2009 at 10:31 AM, randal<[email protected]> wrote: > > > Hello. > > > I'm trying to create a service method that encapsulates a particular > > business logic. I want to make this feature transactional such that > > its job is accomplished atomically(?). The problem is the service > > logic involves accessing different entities that do not belong to the > > same entity group which is not allowed in GAE. > > > At the moment, I've temporarily disabled transaction management to the > > service method. However, I feel I'd need to manage transactions > > eventually. I'm thinking of revising the model design but from how I > > see it, the model classes are good as they are--unrelated by > > ownership. > > > Btw, within the service logic is some methods that are transactional. > > I'm using Spring framework to annotate transaction management. > > > Can anyone help me on how I can go about this? > > > Thanks. --~--~---------~--~----~------------~-------~--~----~ 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] For more options, visit this group at http://groups.google.com/group/google-appengine-java?hl=en -~----------~----~----~----~------~----~------~--~---
