> while manually corrupting the log file

To be fair, since without fsync you don't have any ordering guarantees for your writes, a crash has a good chance of corrupting your data, not just losing recent writes.

That's why in PostgreSQL it's feasible to disable https://www.postgresql.org/docs/18/runtime-config-wal.html#G... but not to disable https://www.postgresql.org/docs/18/runtime-config-wal.html#G....