LDEV-4944 Synchronise VSA answer allocation We need to synchronise this operation. When multiple requests are made to modify the same option…
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LDEV-4944 Synchronise VSA answer allocationWe need to synchronise this operation.When multiple requests are made to modify the same option, for exampleto add a VSA answer, we have a case of dirty reads. One answer getsadded, but while DB is still flushing, another answer reads the optionwithout the first answer, because it is not there yet.The second answer gets added, but the first one gets lost.We can not synchronise the method in service as the "dirty" transactionis already started before synchronisation kicks in.We do it in MonitoringController, before transaction starts.It will not work for distributed environment, though.If teachers allocate answers on different LAMS servers, we can still getthe same problem. We will need a more sophisticated solution then.
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