Steps to reproduce,
- Go to pipeline studio
- Create a pipeline and start the preview.
- Once the preview is running and you are able to see preview data, open concurrently do this in 11 different windows and do the same
- The preview that was started first will start to receive 404 after sometime
This happens because we have a max of 10 concurrent previews that can run and if preview service receives any more it will purge the latest completed preview which causes the UI to show 404 (since everything about the preview is wiped out).
The right solution would be to handle this in the backend and that will come as part of scaling preview.
The very least UI should enable users to get out of the preview mode and start another preview and show appropriate message in the UI about non-availability of preview data.