Re: factorial function/phase out postfix operators?

On Thu, Sep 3, 2020 at 11:50 AM Mark Dilger
<mark(dot)dilger(at)enterprisedb(dot)com> wrote:
> Since newer pg_dump binaries can be used to dump data from older servers, and since users might then load that dump back into an older server, I think doing anything stronger than a pg_log_warning() would be incorrect. I did not find precedents under comparable circumstances for taking stronger actions than pg_log_warning. I assume we can't, for example, omit the operator from the dump, nor can we abort the process.

I'm not sure that this is the right solution. Generally, the
recommendation is that you should use the pg_dump that corresponds to
the server version where you want to do the reload, so if you're
hoping to dump 9.6 and restore on 11, you should be using the pg_dump
from 11, not 14. So my thought would be that if there are user-defined
postfix operators, pg_dump ought to error out. However, that could be
inconvenient for people who are using pg_dump in ways that are maybe
not what we would recommend but which may happen to work but for this
issue, so I'm not sure. On the third hand, though, we think that there
are very few user-defined postfix operators out there, so if we just
give an error, we probably won't be inconveniencing many people.

I'm not sure who is going to commit this work, and that person may
have a different preference than me. However, if it's me, I'd like to
see the removal of the existing postfix operators broken off into its
own patch, separate from the removal of the underlying facility to
have postfix operators.

--
Robert Haas
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