Re: pg18: Virtual generated columns are not (yet) safe when superuser selects from them

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>

To: Christoph Berg <myon@debian.org>

Cc: Robert Haas <robertmhaas@gmail.com>, Peter Eisentraut <peter@eisentraut.org>, Feike Steenbergen <feikesteenbergen@gmail.com>, PostgreSQL mailing lists <pgsql-hackers@postgresql.org>

Date: 2025-06-05T15:46:08Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Restrict virtual columns to use built-in functions and types
- 0cd69b3d7ef3 18.0 landed
Fix virtual generated column type checking for ALTER TABLE
- 49fe1c83ecf3 18.0 landed
Expand virtual generated columns in the planner
- 1e4351af329f 18.0 cited

Christoph Berg <myon@debian.org> writes:
> So the question is, are all built-in *immutable* functions safe?

Perhaps.

> Extending the idea, perhaps the check could be moved to run-time and
> recursively check that only immutable functions are called, including
> user-defined immutable functions?

I don't think I'd trust that.  UDFs can claim to be immutable but
be lying about it.

			regards, tom lane