Hello, Sawada-san
I'll continue the discussion of [2]. We talked about how to recognize the time or LSN when/where wal_level is changed to 'none' there. You said > The use case I imagined is that the user temporarily > changes wal_level to 'none' from 'replica' or 'logical' to speed up loading > and > changes back to the normal. In this case, the backups taken before the > wal_level change cannot be used to restore the database to the point after the > wal_level change. So I think backup management tools would want to > recognize the time or LSN when/where wal_level is changed to ‘none’ in order > to do some actions such as invalidating older backups, re-calculating backup > redundancy etc. > Actually the same is true when the user changes to ‘minimal’. The tools would > need to recognize the time or LSN in this case too. Since temporarily changing > wal_level has been an uncommon use case some tools perhaps are not aware > of that yet. But since introducing wal_level = ’none’ could make the change > common, I think we need to provide a way for the tools. I wondered, couldn't backup management tools utilize the information in the backup that is needed to be made when wal_level is changed to "none" for example ? As I said before, existing backup management tools support only wal_level=replica or logical at present. And, if they would wish to alter the status quo and want to cover the changes over wal_levels, I felt it's natural that they support feature like taking a full backup, trigged by the wal_level changes (or server stop). This is because taking a backup is a must for wal_level=none, as I described in the patch of wal_level=none. For example, they could prepare an easy way to take an offline physical backup when the server stops for changing the wal_level. (Here, they can support the change to minimal, too.) What did you think ? [2] - https://www.postgresql.org/message-id/CAD21AoCotoAxxCmMVz6niwg4j6c3Er_-GboTLmHBft8pALpOGA%40mail.gmail.com Best Regards, Takamichi Osumi
