Re: PoC: Make it possible to disallow WHERE-less UPDATE and DELETE

On Mon, Sep 26, 2016 at 5:48 AM, Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com
> wrote:

> On Mon, Sep 19, 2016 at 4:02 PM, David Fetter <david(at)fetter(dot)org> wrote:
> >
> > [training_wheels_004.patch]
>
> openjade:filelist.sgml:144:16:E: character "_" invalid: only parameter
> literal, "CDATA", "ENDTAG", "MD", "MS", "PI", "PUBLIC", "SDATA",
> "STARTTAG", "SYSTEM" and parameter separators allowed
> openjade:contrib.sgml:138:2:W: cannot generate system identifier for
> general entity "require"
>
> The documentation doesn't build here, I think because require_where is
> not an acceptable entity name. It works for me if I change the
> underscore to a minus in various places. That fixes these errors:
>
> + <para>
> + Here is an example showing how to set up a database cluster with
> + <literal>require_where</literal>.
> +<screen>
> +$ psql -U postgres
> +# SHOW shared_preload_libraries; /* Make sure not to clobber
> something by accident */
> +
> +If you found something,
> +# ALTER SYSTEM SET
> shared_preload_libraries='the,stuff,you,found,require_where';
> +
> +Otherwise,
> +# ALTER SYSTEM SET shared_preload_libraries='require_where';
> +
> +Then restart <productname>PostgreSQL</productname>
> +</screen>
> + </para>
>
> Could use a full stop (period) on the end of that sentence. Also it
> shouldn't be inside the "screen" tags. Maybe "If you found
> something," and "Otherwise," shouldn't be either, or should somehow be
> marked up so as not to appear to be text from the session.
>
> postgres=# delete from foo;
> ERROR: DELETE requires a WHERE clause
> HINT: To delete all rows, use "WHERE true" or similar.
>
> Maybe one of those messages could use some indication of where this is
> coming from, for surprised users encountering this non-standard
> behaviour for the first time?
>
>
+1.

I think hint message should be more clear about where its coming
from. May be it can specify the GUC name, or suggest that if you
really want to use DELETE without WHERE clause, turn OFF this
GUC? or something in similar line.

> FWIW I saw something similar enforced globally by the DBA team at a
> large company with many database users. I think experienced users
> probably initially felt mollycoddled when they first encountered the
> error but I'm sure that some were secretly glad of its existence from
> time to time... I think it's a useful feature for users who want it,
> and a nice little demonstration of how extensible Postgres is.
>
> --
> Thomas Munro
> http://www.enterprisedb.com
>
>
> --
> Sent via pgsql-hackers mailing list (pgsql-hackers(at)postgresql(dot)org)
> To make changes to your subscription:
> http://www.postgresql.org/mailpref/pgsql-hackers
>

--
Rushabh Lathia