Re: [Patch]The Case For WAL-Logging pg_upgrade

On Fri, Jul 31, 2026 at 8:14 PM Bohyun Lee <bohyun(dot)lee(at)databricks(dot)com> wrote:
> The patch closes both gaps by atomically WAL-logging the after-images generated by pg_upgrade upon successful completion. The upgrade becomes part of the WAL stream and can be propagated to standbys through standard streaming replication, eliminating the need for offline rsync-based resynchronization.

This is an interesting proposal. I think a new RMGR that ships a
filesystem transformation through the WAL stream might be a difficult
sell. It's different in that the system must know what file paths to
stick into the WAL stream to get the desired result. It also changes a
lot of the backend to support new capabilities in a frontend tool. If
we're changing this much in the tree, we have other options to arrange
for normal WAL to physically propagate the primary's changes, since
that's a desireable feature. Coincidentally, I've been prototyping
ideas lately as well.

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John Naylor
Amazon Web Services