"Mattias Kregert" <mattias@kregert.se> writes:
> [ misguided analysis ]
> Journalling FS will fix the FS problems, so the files are ok.
> PG journal will fix the PG problems so the tables will be ok.
Only if the journal is all down to disk before the crash.
The fundamental problem with fsync off is that it's likely to violate
the WAL principle (write journal entry before data entry it describes).
If you then crash, you have data entries that correspond to transactions
that should not have been committed (because WAL replay won't guarantee
recovering all of the transaction's effects). In other words, corrupt
data.
If we had a less costly way of guaranteeing write order than fsync, we'd
use it, but there is no other portable method.
regards, tom lane