Re: Deprecating non-select rules (was Re: Last gasp)

On Mon, Apr 09, 2012 at 03:35:06PM +0200, Andres Freund wrote:
> On Monday, April 09, 2012 03:25:36 PM Robert Haas wrote:
> > contrib/xml2 isn't doing us much harm beyond being an ugly wart, but non-
> > SELECT rules are a land mine for the unwary at best.
> Which we could start deprecating now btw. since INSTEAD triggers landed in 
> 9.1. There were quite some use-cases for non-select rules that couldn't be 
> fullfilled before but I think saying that we won't support those rules for 
> more than 3 releases or so might be a good idea. I have seen too many bugs 
> being caused by experienced people not realizing the pitfalls of rules.

A new documentation section "Pitfalls of the Rule System" discussing the known
hazards would help users immediately and be far easier to adopt.  In contrast
to the breathless vitriol against rules that periodically appears on these
lists, current documentation barely hints at the trouble.