Slowdown spikes when moving an object in the scene caused by the PropertyDatabase.

There are some slowdowns when interacting with the scene view, which are caused by the PropertyDatabase. When something is modified in the scene, the SearchMonitor picks up the modifications and sends an invalidation request to the PropertyDatabase (this request only happens every ~2s). The invalidation ends up invalidating data in the PropertyDatabaseFileStore, and flushing the new data to disk, which creates a lag spike.

To fix the issue, we should not invalidate the data in the file store, but in the memory store, and prevent unnecessary flushes to disk.

 

Steps to reproduce:

• Create an empty project
• Add a cube to the scene
• Drag the cube around using gizmos for more than 10s

Expected results:

 No spikes caused by flushing the data to disk.

Actual results:

Spikes caused by flushing the data to disk.