| From: | Martijn van Oosterhout <kleptog(at)svana(dot)org> |
|---|---|
| To: | Andrew Gierth <andrew(at)tao11(dot)riddles(dot)org(dot)uk> |
| Cc: | pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: WITH RECUSIVE patches 0723 |
| Date: | 2008-07-28 22:24:46 |
| Message-ID: | 20080728222446.GC24856@svana.org |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers pgsql-patches |
On Mon, Jul 28, 2008 at 07:57:16PM +0100, Andrew Gierth wrote:
> Which will be a serious pessimization in many common cases if you do
> it all the time. Googling for examples of non-recursive WITH queries
> shows that it is very widely used for clarity or convenience, in
> contexts where you _don't_ want materialization.
Since the problem is using the result of a WITH clause more than once,
would it be sufficient to simply detect that case and bail? You don't
want materialisation is most cases, there's just a few where it is
needed.
Have a nice day,
--
Martijn van Oosterhout <kleptog(at)svana(dot)org> http://svana.org/kleptog/
> Please line up in a tree and maintain the heap invariant while
> boarding. Thank you for flying nlogn airlines.
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