[postgis-devel] Segfault when doing intersections (BUG)

[Mark Cave-Ayland]

w s wrote:

> Hi all,
> 
> Summary:  when doing intersections, I occasionally get a failed backend.
> 
> I am having an intermittent segfault using the st_ intersection() on 
> some big polygons.  I will post more as I have more time, but I think I 
> can give enough info here to be a useful start.
> 
> I don't have a big enough machine or enough time to rebuild with all the 
> debug stuff enabled and keep log files, at least in the next week.  With 
> some guidance, though, I would happily try to get a core or a gdb dump 
> or whatever would help.  I built postgis with debug enabled and ran out 
> of disk space...., so I went back to the regular.
> 
> Note: I am getting errors when using proprietary data that I have 
> shp2pgsql'ed, so I can't provide that.  The data is census tracts and 
> zipcodes for two states, along with associated data for populations.
> 
> I have attached a script that runs a sql script over and over again 
> until I get a failure.  I also attached the SQL script.  It always 
> happens on the CREATE TABLE near the end. 
> 
> Log output:
> pgsql[0]$ LOG:  database system was shut down at 2009-11-15 12:44:59 PST
> LOG:  database system is ready to accept connections
> LOG:  autovacuum launcher started
> LOG:  server process (PID 29206) was terminated by signal 11: 
> Segmentation fault
> LOG:  terminating any other active server processes
> WARNING:  terminating connection because of crash of another server process
> DETAIL:  The postmaster has commanded this server process to roll back 
> the current transaction and exit, because another server process exited 
> abnormally and possibly corrupted shared memory.
> HINT:  In a moment you should be able to reconnect to the database and 
> repeat your command.
> LOG:  all server processes terminated; reinitializing
> LOG:  database system was interrupted; last known up at 2009-11-15 
> 12:45:46 PST
> LOG:  database system was not properly shut down; automatic recovery in 
> progress
> LOG:  redo starts at 1/6BE203D4
> LOG:  unexpected pageaddr 1/657BC000 in log file 1, segment 108, offset 
> 8110080
> LOG:  redo done at 1/6C7BBFB0
> LOG:  database system is ready to accept connections
> LOG:  autovacuum launcher started
> 
> SQL statement at which point we died:
> 
> create table crosswalk as
>         select a.id <http://a.id> as zip, b.id <http://b.id> as 
> tractfips, 0.0 as area, 0.0 as propzip, 0.0 as proptract,
>                                 st_intersection(a.the_geom, b.the_geom) 
> as the_geom, a.the_geom as zip_geom, b.the_geom as tract_geom
>                 from orwa_zp a , orwa_tr b
>                 where st_intersects(a.the_geom, b.the_geom);
> 
> wsprague=# select * from postgis_full_version()
> wsprague-# ;
>                                   
> postgis_full_version                                 
> ----------------------------------------------------------------------------------------
>  POSTGIS="1.4.0" GEOS="3.1.1-CAPI-1.6.0" PROJ="Rel. 4.7.1, 23 September 
> 2009" USE_STATS
> (1 row)
> 
> 
> wsprague=# select * from version();
>                                                                      
> version                                                                    
> -------------------------------------------------------------------------------------------------------------------------------------------------
>  PostgreSQL 8.4.1 on i386-apple-darwin8.11.1, compiled by GCC 
> i686-apple-darwin8-gcc-4.0.1 (GCC) 4.0.1 (Apple Computer, Inc. build 
> 5367), 32-bit
> (1 row)


Hi Webb,

I've been meaning to add some notes to the wiki regarding getting a 
backtrace from gdb when PostGIS/PostgreSQL crashes for a while. Can you 
take a look at 
http://trac.osgeo.org/postgis/wiki/DevWikiGettingABackTrace and see if 
that is detailed enough for you to get the required information?


ATB,

Mark.

-- 
Mark Cave-Ayland - Senior Technical Architect
PostgreSQL - PostGIS
Sirius Corporation plc - control through freedom
http://www.siriusit.co.uk
t: +44 870 608 0063

Sirius Labs: http://www.siriusit.co.uk/labs