Re: [PATCH] Refactor SLRU to always use long file names

Hi Heikki,

> Since commit bd8d9c9bdf "Widen MultiXactOffset to 64 bits",
> "pg_multixact/members" should not be in that list anymore.

I missed this one. Fixed, thanks.

> Also, it seems misleading that a function called "check_*" doesn't
> merely check for things, but renames files.

Fair point. I renamed it to `ensure_long_slru_segment_filenames`.

> Could we copy/link them with the new long names to begin with?

That's an interesting idea.

What I personally don't like about it is the fact that a single
migration will affect the logic of every run of pg_upgrade, even in
the far future, for instances that don't need this migration.
Previously I showed [1] that the entire migration takes little time
(note that we had to migrate pg_multixact/members back then). So I
don't think this optimization is a good idea in the long run, unless
we reach a consensus on the opposite.

[1]: https://www.postgresql.org/message-id/CAJ7c6TPdDSnVR2ZGn-oirfvvFXZghS5PAXYwmtb7_nNps53eEg%40mail.gmail.com

-- 
Best regards,
Aleksander Alekseev