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

On 05/08/2026 08:15, John Naylor wrote:
> I think my phrasing was ambiguous: When I said "the system must know
> what file paths to stick into the WAL stream", I didn't mean creating
> path strings, I meant the enumeration done by capture_all_relfiles()
> etc. Normally, a WAL record enters the stream because a logged write
> happens. In the patch, the input to WAL comes from a directory walk of
> already-written files. If this walk misses anything, then the standby
> diverges from the primary.

It'd be pretty hard to screw up walking all files in a directory ;-). I
don't think missing some files is a serious concern.

For comparison, the GIN and GiST index build also work by first building
the whole index, and then WAL-logging the result as a separate step.
There's precedent in pg_rewing too, which also walks the data directory,
copies all files it doesn't recognize as is, and has special handling
for relation files.

- Heikki