Re: Pro et contra of preserving pg_proc oids during pg_upgrade - Mailing list pgsql-hackers

From David G. Johnston
Subject Re: Pro et contra of preserving pg_proc oids during pg_upgrade
Date
Msg-id CAKFQuwYworUX1DCkc3WB82Ld2mkB+HB_uasnqkN0DWwc7zCBdg@mail.gmail.com
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In response to Re: Pro et contra of preserving pg_proc oids during pg_upgrade  (Nikita Malakhov <hukutoc@gmail.com>)
List pgsql-hackers
On Thu, Oct 12, 2023 at 2:58 PM Nikita Malakhov <hukutoc@gmail.com> wrote:
Why pg_upgrade cannot be used?

We document both a pg_dump/pg_restore migration and a pg_upgrade one (not to mention that logical backup and restore would cause the oids to change).  It seems odd to have a feature that requires pg_upgrade to be the chosen one.  pg_upgrade is an option, not a requirement.  Same goes for pg_basebackup.

pg_upgrade itself warns that should the on-disk file format change then it would be unusable - though I suspect that we'd end up with some kind of hybrid approach in that case.
 
OID preservation logic is already implemented
for several OIDs in catalog tables, like pg_class, type, relfilenode, enum...


We are allowed to preserve oids if we wish but that doesn't mean we must, nor does doing so constitute a declaration that such oids are part of the public API.  And I don't see us making OIDs part of the public API unless we modify pg_dump to include them in its output.


Actually, I've asked here because there are several references to PG_PROC oids
from other tables in the system catalog

Of course there are, e.g., views depending on functions would result is those.  But pg_upgrade et al. recomputes the views so the changing of oids isn't a problem.

Long text fields are common in databases; and if there are concerns with parsing/interpretation we can add functions to make doing that simpler.

David J.

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