On 06/08/2026 01:17, John Naylor wrote:
On Wed, Aug 5, 2026 at 9:36 PM Bohyun Lee
<[email protected]> wrote:
The GUCs are introduced because we cannot assume the standby's
storage layout exactly matches the primary's, neither where the
retained pre-upgrade directory sits, nor how its files are
physically placed. It also depends on how the cluster intends to
use the standby. For instance, if the operator wants to keep the
standby as a rollback target, it may be worthwhile to use a
different transfer mode via the newly introduced
pg_upgrade_standby_transfer_mode GUC, which I believe is useful.
Nevertheless, the reconstructed cluster will be logically
identical, even if the physical representation diverges.
Given the above design concepts, I still think WAL is fundamentally
the wrong mechanism for this.
Can you elaborate? Do you think the changes that pg_upgrade makes should
be written somewhere else than WAL, or is this just about the transfer
mode setting, or something else? How would you do it?
- Heikki
