Overview
As there may be cancelled background tasks visible in M-Files Admin's Background Tasks section, a question is often raised whether it is possible to cancel some long running tasks for various reasons, including performance effects or wish to cancel an operation such as a change of a NACL or property modifications of a class.Solution
Even though there may be cancelled background tasks visible, it is not possible to cancel a background task. This is because the background task is triggered when a change is done and the change is then applied in the background. If a task were cancelled, it would mean that certain setting, such as a NACL change, has been done and some objects in the vault associated with such NACL were updated and some were not. This would leave the vault into a non-consistent state.The fact that there are cancelled tasks is related to certain optimizations where, under certain circumstances, M-Files Server combines several tasks into one larger task which can then be run more efficiently.
There are some exceptions to the above but those have to be considered case by case together with M-Files customer support.
The amount of parallelism of those tasks can be adjusted via the Configurations section of the vault, under Advanced Vault Settings / Configuration / Background Task. Vault needs to be taken offline and then online to apply the new settings. The higher the parallelism the higher the load is in the vault database.
