Re: psql: Add leakproof field to \dAo+ meta-command results

Hi,

On Tue, 30 Jul 2024 01:36:55 +0200
Erik Wienhold <ewie(at)ewie(dot)name> wrote:

> On 2024-07-01 15:08 +0200, Yugo NAGATA wrote:
> > I would like to propose to add a new field to psql's \dAo+ meta-command
> > to show whether the underlying function of an operator is leak-proof.
>
> +1 for making that info easily accessible.
>
> > This idea is inspired from [1] that claims some indexes uses non-LEAKPROOF
> > functions under the associated operators, as a result, it can not be selected
> > for queries with security_barrier views or row-level security policies.
> > The original proposal was to add a query over system catalogs for looking up
> > non-leakproof operators to the documentation, but I thought it is useful
> > to improve \dAo results rather than putting such query to the doc.
> >
> > The attached patch adds the field to \dAo+ and also a description that
> > explains the relation between indexes and security quals with referencing
> > \dAo+ meta-command.
> >
> > [1] https://www.postgresql.org/message-id/raw/5af3bf0c-5e0c-4128-81dc-084c5258b1af%40code406.com
>
> \dAo+ output looks good.

Thank you for looking into this.
I attached a patch updated with your suggestions.

>
> But this patch fails regression tests in src/test/regress/sql/psql.sql
> (\dAo+ btree float_ops) because of the new leak-proof column. I think
> this could even be changed to "\dAo+ btree array_ops|float_ops" to also
> cover operators that are not leak-proof.

Thank you for pointing out this. I fixed it with you suggestion to cover
non leak-proof operators, too.

> +<para>
> + For example, an index scan can not be selected for queries with
>
> I check the docs and "cannot" is more commonly used than "can not".

Fixed.

>
> + <literal>security_barrier</literal> views or row-level security policies if an
> + operator used in the <literal>WHERE</literal> clause is associated with the
> + operator family of the index, but its underlying function is not marked
> + <literal>LEAKPROOF</literal>. The <xref linkend="app-psql"/> program's
> + <command>\dAo+</command> meta-command is useful for listing the operators
> + with associated operator families and whether it is leak-proof.
> +</para>
>
> I think the last sentence can be improved. How about: "Use psql's \dAo+
> command to list operator families and tell which of their operators are
> marked as leak-proof."? Should something similar be added to [1] which
> also talks about leak-proof operators?

I agree, so I fixed the sentence as your suggestion and also add the
same description to the planner-stats-security doc.

> The rest is just formatting nitpicks:
>
> + ", ofs.opfname AS \"%s\"\n,"
>
> The trailing comma should come before the newline.
>
> + " CASE\n"
> + " WHEN p.proleakproof THEN '%s'\n"
> + " ELSE '%s'\n"
> + " END AS \"%s\"\n",
>
> WHEN/ELSE/END should be intended with one additional space to be
> consistent with the other CASE expressions in this query.

Fixed both.

Regards,
Yugo Nagata

>
> [1] https://www.postgresql.org/docs/devel/planner-stats-security.html
>
> --
> Erik

--
Yugo NAGATA <nagata(at)sraoss(dot)co(dot)jp>