Re: WITH RECURSIVE patches V0.1 TODO items

On Tue, May 27, 2008 at 12:40:58PM +0900, Tatsuo Ishii wrote:
> > > - cost of Recursive Scan is always 0
> > 
> > This should probably be fixed, but it leads to problems like:
> > 
> > > - infinit recursion is not detected
> > > 
> > >   * Tom suggested let query cancel and statement_timeout handle it.
> > 
> > Right for this case.  Is there some way to estimate this short of
> > a full-on materialized views implementation?  I'm guessing we'd
> > need to be able to cache the transitive closure of such searches.
> 
> I did some discussion with Gregory Stark and Michael Makes at PGCon.
> We tend to agree that very low constant cost for Recursive Scan
> (probably plain 0 is not good though) is not so bad, since this
> would emit plan which hashes the result of Recusive scan in a hash
> join plan which is probably not so bad for most cases.

It's good to know someone with the knowledge has some better estimate :)

> Also I talked with him that it would be nice we could have a kind of
> distributed source repository to co-develop patches.

This is just the kind of thing git
<http://wiki.postgresql.org/wiki/Working_with_Git> was designed for.

Who has tried it in your organization?

Cheers,
David.
-- 
David Fetter <david@fetter.org> http://fetter.org/
Phone: +1 415 235 3778  AIM: dfetter666  Yahoo!: dfetter
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