We have experienced catastrophic data loss several times, and there is currently no way to do any sort of troubleshooting within Microsoft CDS.
We are moving away from the CDS altogether at this point, because of the numerous issues and outages we have experienced.
Examples of issues that we are unable to fix or troubleshoot due to lack of tools:
https://powerusers.microsoft.com/t5/PowerApps-Forum/CDS-data-loss/m-p/25177
https://powerusers.microsoft.com/t5/PowerApps-Forum/CDS-Error-and-Data-missing/m-p/27733#M11698
https://powerusers.microsoft.com/t5/PowerApps-Forum/Yet-another-CDS-Data-Error/td-p/27624
We are looking into more robust server options until Microsoft can make the CDS more stable, or at least provide users with the tools necesarry to troubleshoot these problems.
I appreciate you posting these examples of instability. Our priorities revolve around performance and stability, so we appreciate your patience as we continue to mitigate the risk of failures.