Re: CTE bug?

On Tue, Sep 08, 2009 at 11:37:14PM -0400, Tom Lane wrote:
> I wrote:
> > David Fetter <david(at)fetter(dot)org> writes:
> >> WITH RECURSIVE t(j) AS (
> >> WITH RECURSIVE s(i) AS (
> >> VALUES (1)
> >> UNION ALL
> >> SELECT i+1 FROM s WHERE i < 10
> >> ) SELECT i AS j FROM s
> >> UNION ALL
> >> SELECT j+1 FROM t WHERE j < 10
> >> )
> >> SELECT * FROM t;
> >> ERROR: relation "s" does not exist
> >> LINE 6: ) SELECT i AS j FROM s
> >> ^
> >> Shouldn't this work?
>
> > Huh, nice test case. It looks like it's trying to do the
> > "throwaway parse analysis" of the nonrecursive term (around line
> > 200 of parse_cte.c) without having analyzed the inner WITH clause.
> > We could probably fix it by doing a throwaway analysis of the
> > inner WITH too ... but ... that whole throwaway thing is pretty
> > ugly and objectionable from a performance standpoint anyhow. I
> > wonder if it wouldn't be better to refactor so that
> > transformSetOperationStmt knows when it's dealing with the body of
> > a recursive UNION and does the analyzeCTETargetList business after
> > having processed the first UNION arm.
>
> I've committed a fix along those lines. Too late for 8.4.1
> unfortunately :-(.

I just wish I'd found it sooner :)

Cheers,
David.
--
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter
Skype: davidfetter XMPP: david(dot)fetter(at)gmail(dot)com

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