Re: [HACKERS] WITH RECURSIVE updated to CVS TIP - Mailing list pgsql-patches

From Hans-Juergen Schoenig
Subject Re: [HACKERS] WITH RECURSIVE updated to CVS TIP
Date
Msg-id E85BEA16-60E4-419C-BD3F-C2DB7578DC58@cybertec.at
Whole thread Raw
In response to WITH RECURSIVE updated to CVS TIP  (David Fetter <david@fetter.org>)
Responses Re: [HACKERS] WITH RECURSIVE updated to CVS TIP  (David Fetter <david@fetter.org>)
Re: [HACKERS] WITH RECURSIVE updated to CVS TIP  (Yoshiyuki Asaba <y-asaba@sraoss.co.jp>)
List pgsql-patches
hello david,

i did some quick testing with this wonderful patch.
it seems there are some flaws in there still:

test=# explain select count(*)
test-#         from ( WITH RECURSIVE t(n) AS ( SELECT 1 UNION ALL SELECT DISTINCT n+1 FROM t )
test(#                 SELECT * FROM t WHERE n < 5000000000) as t
test-#         WHERE n < 100;
server closed the connection unexpectedly
        This probably means the server terminated abnormally
        before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.
!> \q

this one will kill the planner :(
removing the (totally stupid) distinct avoids the core dump.


i found one more issue;

-- broken: wrong result
test=# select count(*) from ( WITH RECURSIVE t(n) AS (
        SELECT 1 UNION ALL SELECT n + 1 FROM t)
        SELECT * FROM t WHERE n < 5000000000) as t WHERE n < (
                select count(*) from ( WITH RECURSIVE t(n) AS (
                        SELECT 1 UNION ALL SELECT n + 1 FROM t )
        SELECT * FROM t WHERE n < 5000000000) as t WHERE n < 100) ;
 count
-------
     1
(1 row)

if i am not totally wrong, this should give us a different result.

i am looking forward to see this patch in core :).
it is simply wonderful ...

many thanks,

hans






On Jul 3, 2008, at 1:11 AM, David Fetter wrote:

Folks,

Please find patch enclosed, including some documentation.

Can we see about getting this in this commitfest?

Cheers,
David.
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Phone: +1 415 235 3778  AIM: dfetter666  Yahoo!: dfetter
Skype: davidfetter      XMPP: david.fetter@gmail.com

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