Re: Deprecating RULES

On 11 October 2012 20:28, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
> Not many RULE-lovers out there, once you've tried to use them.
>
> Allowing RULEs complicates various things and can make security more difficult.

What exactly do they make more difficult? Are you particularly
concerned with the overhead that rules impose when developing certain
types of features? If so, since there's going to be a legacy
compatibility mode for a long time, I don't know that deprecating
rules will buy you much in the next 3 - 4 releases.

> For 9.3, I suggest we create a DDL trigger by default which prevents
> RULEs and throws an ERROR that explains they are now deprecated.
>
> Anybody that really cares can delete this and use them. Sometime in
> future, we hard code it, barring complaints.

Well, rules have been around since the Berkeley days [1]. I don't
think that anyone, including Tom, is willing to argue that
user-defined rules are not a tar-pit (except perhaps ON SELECT DO
INSTEAD SELECT rules - which are exactly equivalent to views anyway).
Personally, I'd like to see them removed too. However, in order to be
able to get behind your proposal, I'd like to see a reasonably
developed cost/benefit analysis. People do use user-defined rules. For
example, the xTuple open source ERP package uses ON INSERT DO INSTEAD
rules [2].

[1] http://db.cs.berkeley.edu/papers/ERL-M89-82.pdf

[2] http://www.xtuple.org/ApiDevelopment

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Peter Geoghegan http://www.2ndQuadrant.com/
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