Re: SEGFAULT on SELECT * FROM view

On Mon, Jan 2, 2012 at 1:42 AM, chris r. <chricki(at)gmx(dot)net> wrote:
>>> I ported the entire schema to my test DB server and could not reproduce
>>> the error there. Note that probably recreating the view solves this
>>> issue. Given this, how should I proceed to create a test case? Any
>>> tutorial on this? (I'm not too familiar with all this yet.)
>>
>> It's possibly statistics-dependent; make sure you have the same stats
>> targets on both DBs, and try re-analyzing a few times.  Check other
>> planner parameters are the same, too.
> In addition to the schema, I now also copied parts of the data in our
> production system to the testing DB. (I cannot copy all data, as it's
> too large for the testing DB.) After a couple of VACUUM FULL ANALYZEs,
> the bug still doesn't reproduce.
>
> In our production environment, I'm working with the re-created view that
> doesn't show the SEGFAULT behavior. I can live with this workaround, as
> only one particular view seems to be affected, but if you want me to
> debug more on the error please let me know.

It would be awfully nice to figure out what was going on. Another
thing that would help, if you can still reproduce the error, would be
to get a stack trace. The easiest way would probably be to enable
core dumps (pg_ctl -c start, or ulimit -c unlimited followed by pg_ctl
start). Then, when you get a core, which might end up inside $PGDATA
or perhaps elsewhere depending on your system configuration, do:

gdb /path/to/postgres /path/to/corefile

and then from within gdb:

bt

...to get a backtrace.

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