Hello
> as far as I understand these restrictions apply when hot_standby is set to on AND a recovery.conf is missing.
When hot_standby is set to on AND a recovery.conf is PRESENT
Here is: https://github.com/postgres/postgres/blob/REL_10_STABLE/src/backend/access/transam/xlog.c#L6185
ArchiveRecoveryRequested is set if we found recovery.conf (see readRecoveryCommandFile)
> I can confirm that hot_standby is commented out - is this setting on by default?
Yes, in postgresql 10 and newer.
regards, Sergei