Re: No discussion of custom variables; no "See also" for set_config, current_setting, pg_settings - Mailing list pgsql-docs
Thanks for the quick response.
It’s a clearly useful, simplifying feature. Unless it is likely to be removed at some point, I propose it should be documented and declared supported wherever relevant.
In any event, I am happy to prepare some documentation changes that mention these caveats, but I won’t if there is no chance of it being accepted. Are we totally opposed?
On Sep 2, 2022, at 15:16 , Tom Lane <tgl@sss.pgh.pa.us> wrote:PG Doc comments form <noreply@postgresql.org> writes:A reader of this section
https://www.postgresql.org/docs/current/sql-set.html of the documentation
might be forgiven for thinking that Postgres does not support custom
variables.
They are, in fact, *not* a supported feature. The only intended use
of non-core GUCs was for extensions' parameters. People have abused the
mechanism to create ad-hoc session variables, but we don't encourage it.
The underlying code won't scale to large numbers of variables, there's
no way to declare properties of such a variable in SQL, etc.
There's been an ongoing effort to create a respectable substitute,
but it still hasn't gotten across the finish line [1].
regards, tom lane
[1] https://commitfest.postgresql.org/39/1608/
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