This report is primarily intended for companies, specifically their IT departments, that are running Russian systems 1C 8.x and have the ability to work with both MSSQL Server and PostgreSQL. We live in a unique time when having a heterogeneous IT system (a system with a distributed architecture where each database instance runs under different databases and/or has a different data structure) is justified both economically and in terms of potential risks. On the one hand, we store data and use databases with predictable behavior and open source code, regardless of the political situation. On the other hand, with this approach, we take advantage of all the benefits (primarily performance) of a powerful database supported by the largest vendor, albeit a hostile state to us. Now is the time to assess risks with the necessary level of paranoia. After all, data can be corrupted not only at the level of storage logic, but also by the method of additional "hidden" calls of Delete/Update constructs at the engine level of the database. Therefore, it is now relevant not only to monitor the performance of the IT system, but also to audit data and their timely integrity. It is necessary to implement data verification procedures, it is necessary to implement procedures for closing periods, procedures for fault-tolerant storage. And accordingly, to provide for various threat models in data recovery procedures. The report presents options for countering such threats and scenarios for the most seamless transition of large databases to PostgreSQL, since it is precisely for such databases that the problem of translating to a new DBMS is particularly acute.