Horton

Re: BUG #18178: New Restriction on "ON SELECT" rules on tables

Laurenz Albe <laurenz.albe@cybertec.at>

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From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Joshua Uyehara <joshua.uyehara@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-bugs@lists.postgresql.org
Date: 2023-11-03T15:21:10Z
Lists: pgsql-bugs

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On Fri, 2023-11-03 at 00:44 -1000, Joshua Uyehara wrote:
> As far as the documentation error, on closer review, Part V, 41.2 ("Views and the Rules system")
> was updated to reflect the change, but the Reference entry for Create Rule in Part VI was not:
> 
> > Presently, ON SELECT rules must be unconditional INSTEAD rules and must have actions that
> > consist of a single SELECT command. Thus, an ON SELECT rule effectively turns the table into
> > a view, whose visible contents are the rows returned by the rule's SELECT command rather than
> > whatever had been stored in the table (if anything). It is considered better style to write a
> > CREATE VIEW command than to create a real table and define an ON SELECT rule for it.

Yes, that paragraph has to go.

But I wonder if it would not be better to completely remove ON SELECT from the CREATE RULE
command.  Attached is a patch that does that.

The documentation part of this patch should be backpatched to v16, but the rest is
HEAD only.

Yours,
Laurenz Albe

Commits

  1. Doc: update CREATE RULE ref page's hoary discussion of views.

  2. Remove logic for converting a table to a view.