On Mon, Aug 22, 2011 at 4:16 PM, Erik Rijkers <er@xs4all.nl> wrote:
> I am developing against 9.1beta3 and encountered this problem. I repeated it against rc1 (or
> actually, REL9_1_STABLE taken from git today).
>
> The below SQL causes:
>
> TRAP: FailedAssertion("!(item_width > 0)", File: "costsize.c", Line: 3274)
>
> and the session crashes.
>
> select *
> from (
> select
> col1
> , col2
> , reviewed
> from
> (values
> ( 1111, 'aweyu', 3)
> , ( 2222, 'bwetu', 2)
> , ( 3333, 'vwxyz', 1)
> )
> as r(col1,col2,col3)
> left join (
> select 1 as reviewed, c2 from ( values ('abcde') ) as t1(c2)
> union all select 0 as reviewed, c2 from ( values ('vwxyz') ) as t2(c2)
> )
> as up_all on up_all.c2 = r.col2
> order by col3
> )
> as f
> ;
>
>
> To simplify I used 'values' for the actual tables that I am using, but the above still causes the
> FailedAssertion.
>
> Removing the outer select avoids the error and
> removing order by avoids the error
I can reproduce this on master but not on 9.0. I suspect the problem
was introduced by this commit:
commit 0f61d4dd1b4f95832dcd81c9688dac56fd6b5687
Author: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri Nov 19 17:31:50 2010 -0500
Improve relation width estimation for subqueries.
...but I haven't confirmed that yet.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
