Re: Stronger safeguard for archive recovery not to miss data

On Thu, 2021-01-21 at 11:49 +0000, osumi.takamichi@fujitsu.com wrote:
> Adding a condition to check if "recovery_allow_data_corruption" is 'on' around the end of
> CheckRequiredParameterValues() sounds safer for me too, although
> implementing a new GUC parameter sounds bigger than what I expected at first.
> The default of the value should be 'off' to protect users from getting the corrupted server.
> Does everyone agree with this direction ?

I'd say that adding such a GUC is material for another patch, if we want it at all.

I think it is very unlikely that people will switch from "wal_level=replica" to
"minimal" and back very soon afterwards and also try to recover past such
a switch, which probably explains why nobody has complained about data corruption
generated that way.  To get the server to start with "wal_level=minimal", you must
set "archive_mode=off" and "max_wal_senders=0", and few people will do that and
still expect recovery to work.

My vote is that we should not have a GUC for such an unlikely event, and that
stopping recovery is good enough.

Yours,
Laurenz Albe