Reloading an app updates it with the latest data from the app data sources. The QRS API or engine API can be used to trigger a reload but there are differences in how these APIs handle the requests.
The Engine does not limit the number of concurrent reloads so the reload requests will be placed in a queue, which may cause the Engine to be overloaded by reload calls. Note that the behavior of the Engine API also applies to the Data Load Editor. If several app developers trigger reloads through the Data Load Editor, the Engine will not limit the number of concurrent reloads.
When using the QRS API, the Scheduler service has a mechanism to control the number of concurrent reload tasks. It will recognize existing reloads currently in progress and discard the other tasks.
It is useful to keep in mind that, in this scenario and in the case of using a synchronous repository API call, the expected GUID returned is: 00000000-0000-0000-0000-000000000000.
