When writing integrations that perform numerous simultaneous transactions or many transactions in a rapid succession, a transaction may fail with a concurrency exception.  The error returned may appear as follows:

{"CreateResult": {"_rallyAPIMajor": "1", "_rallyAPIMinor": "43", "Errors": ["Concurrency conflict: [Object has been modified since being read for update in this context] - ConcurrencyConflictException : Modified since read on update : Object Class : com.f4tech.slm.domain.Subscription : ObjectID : 100000001"], "Warnings": [ ]}}

This issue is frequently seen in multi-threaded applications where the external application is sending multiple update requests at the same time.

This is not an issue with the newly created or modified object being updated, but usually more related to synchronization of data between application servers in our cluster.  Editing the same object at the same time can cause this, as could revising a two objects that performs a cascade update to the same parent/child.

Release:
Component: ACSAAS

This can be mitigated by the following suggestions:

• Having the app work in a single-threaded mode thereby sending requests one at a time with a slight delay
• Capturing JSESSIONID from your initial headers and passing that in subsequent requests to stay attached to a single application server
• Trap/detect the error and retry the request again