Asynchrous calls cause StaleObjectStateException
- by Mulone
Hi all,
I'm struggling with a Grails service.
The service gets AJAX calls from the clients and behaves like a simple local cache for remote objects:
void **someCallFromClient**() {
// extract params
def results = remoteService.queryService(params)
results.each{
// try to fetch result object from local DB
def obj = SomeClass.findBySomeField(result.someField)
if (!obj){
obj = new Result(params)
obj.save()
}
// do stuff on obj
}
}
The service works fine when only one client is connected, but as soon as 2 or more clients start bombing the server with requests, I start getting:
2010-05-24 13:09:49,764 [30893094@qtp-26315919-2] ERROR errors.GrailsExceptionResolver
- Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [ some object #892901]
org.hibernate.StaleObjectStateException:
Row was updated or deleted by another transaction
(or unsaved-value mapping was incorrect): [ some object #892901]
// very long stactrace
It probably happens when 2 calls are trying to create the same object concurrently.
I suppose this is a rather typical situation to end up in.
Could you recommend any pattern/good practice to fix this issue?
For example, is there a way to say to one of the service instances to hang on and wait for the other to finish its stuff and try again?
Cheers!
