Re: [sqlsmith] Crash in apply_projection_to_path

On Thu, Apr 28, 2016 at 10:06 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Andreas Seltenreich <seltenreich(at)gmx(dot)de> writes:
>> the following query against the regression database crashes master as of
>> 23b09e15.
>
>> select 1 from depth0 inner join depth1 on (depth0.c = depth1.c)
>> where depth0.c @@ depth1.c limit 1;
>
> What's going on here is that add_partial_path is recycling a now-dominated
> partial path without regard for the fact that there's already a GatherPath
> pointing at that old partial path. Later use of the GatherPath tries to
> make use of its now-dangling subpath pointer.
>
> I'd be inclined to think that it's silly to build GatherPaths in advance
> of having finalized the list of partial paths for a rel.

Uh ... yeah, that shouldn't be happening. I obviously screwed something up.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company