Hi Tim - there's a couple of reasons why this won't work - firstly, it is my understanding that named tasks are also subject to the possibility of being executed twice (the name only prevents the same name being added to the queue twice), and secondly tasks raised transactionally cannot have a task name.
On Apr 23, 11:45 am, Tim Hoffman <[email protected]> wrote: > Probably the best way to guard would be have the task name specific to > the operation. > You cant have another task with the same name for about a week, > > T > > On Apr 23, 3:51 pm, hawkett <[email protected]> wrote: > > > > > > > HI, > > > I understand that it is possible for a single task to be executed more > > than once, but is it safe to assume that only one instance of a > > specific task will be executing at the one time? It makes it much more > > difficult (time consuming) to implement idempotent behaviour if it is > > possible for the subsequent executions of a task to begin before the > > first has completed - i.e. for the same task to be executing > > concurrently. I can think of ways of using db locking (memcache is not > > reliable - especially when this scenario is most likely to occur > > during system failures) to recognise the multiple concurrent > > executions, but it would be great to know that this scenario cannot > > occur. Thanks, > > > Colin > > > -- > > 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.
