This is how a database tells how isolated a task is from other tasks in the database. See: https://docs.microsoft.com/en-us/dotnet/api/system.data.isolationlevel

In MDriven, set one isolation level for update, UpdateIsolationLevel, and one for read, FetchIsolationLevel, in SqlDatabaseConfig.

If you have too low an UpdateIsolationLevel, the extraction of new IDs and timestamps may not be unique and may cause problems with your data integrity.