> The database relies on the data being consistent when it performs crash > recovery. > Imagine that a checkpoint is running while you take your snapshot. The > checkpoint > syncs a data file with a new row to disk. Then it writes a WAL record and > updates > the control file. Now imagine that the table with the new row is on a > different > file system, and your snapshot captures the WAL and the control file, but not > the new row (it was still sitting in the kernel page cache when the snapshot > was taken). > You end up with a lost row. > > That is only one scenario. Many other ways of corruption can happen.
Can we say then that the risk comes only from the possibility of a checkpoint running inside the time gap between the non-simultaneous snapshots?
