Re: Fast default stuff versus pg_upgrade

Hi,

On 2018-06-19 11:51:16 -0400, Andrew Dunstan wrote:
> My initial thought was that as a fallback we should disable pg_upgrade on
> databases containing such values, and document the limitation in the docs
> and the release notes. The workaround would be to force a table rewrite
> which would clear them if necessary.

I personally would say that that's not acceptable. People will start
using fast defaults - and you can't even do anything against it! - and
suddenly pg_upgrade won't work. But they will only notice that years
later, after collecting terrabytes of data in such tables.

If we can't fix it properly, then imo we should revert / neuter the
feature.

> Have we ever recommended use of pg_upgrade for some manual catalog fix after
> release? I don't recall doing so. Certainly it hasn't been common.

No, but why does it matter? Are you arguing we can delay pg_dump support
for fast defaults to v12?

Greetings,

Andres Freund