Re: Rules: A Modest Proposal

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> At the moment, user-accessible RULEs have, as far as I know,
> just two sane uses:
>
> * Writing to VIEWs
> * Routing writes to partitions

Maybe you need a larger clientele list, because I still run up against
RULEs in production environments that don't fit into the categories
above. Here's one I came across just a couple weeks ago. Names changed
for privacy:

CREATE RULE update_other_table
AS ON INSERT TO myschema.mytable
DO ALSO
INSERT INTO myschema.othertable (col1,col2,col3)
VALUES (NEW.col1, NEW.col2, NEW.col3);

Could this be done with a trigger? Yes, but on the plus rules side:

* It's faster
* It's easier to write
* It's immediately viewable as to what is going on with a \d mytable
* Dropping it won't leave an unused function around
* We can still do ALTER TABLE DISABLE TRIGGER ALL

I can give more examples, if you like, but removing a major feature of
Postgres with no real justificatgion seems a bit hasty, to say the least.

> They're mostly a foot-gun.

Lots of things in Postgres could be considered potential foot guns. Frankly,
I don't think rules are even near the top of such a list. Can you give
examples of rule foot guns?

- --
Greg Sabino Mullane greg(at)turnstep(dot)com
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