Topology - toTopoGeom causes segmentation fault and database restart

[Franck Theeten]

I had similar issue recently. This could be caused by a recursive function call  entering an endless loop. In my case checking the code and defining in the problematic function a limit for the depth of recursive calls solved the issue.

Franck Theeten
________________________________
From: Michal Seidl <michal.seidl at gmail.com>
Sent: Wednesday, June 18, 2025 11:36
To: postgis-users at lists.osgeo.org <postgis-users at lists.osgeo.org>
Subject: Topology - toTopoGeom causes segmentation fault and database restart

Hello,
we use postgis topology for storing and updating quite complicated
polygons representing roads.

Sometimes inserting new polygon into topology causes exceptions (whis is
not nice but acceptable, I can see there is plan to add some more
usefull message https://trac.osgeo.org/postgis/ticket/5889) but
sometimes it completely shut down server which is quite bad as there are
other live databases on server.

The error is cause by our function jt_to_topo_geom() which is just
wrapper about toTopoGeom(). The inserted MultiPolygon geometry is quite
large but postgis valid with reasonable vertices. I have suspicion there
is conflict with data already inserted into topology, but have no idea
where due to not info from log.

Postgis:

POSTGIS="3.4.2 c19ce56" [EXTENSION] PGSQL="140" GEOS="3.9.0-CAPI-1.16.2"
PROJ="7.2.1 NETWORK_ENABLED=OFF URL_ENDPOINT=https://cdn.proj.org
USER_WRITABLE_DIRECTORY=/tmp/proj DATABASE_PATH=/usr/share/proj/proj.db"
LIBXML="2.9.10" LIBJSON="0.15" LIBPROTOBUF="1.3.3" WAGYU="0.5.0
(Internal)" TOPOLOGY

The code of function:

CREATE OR REPLACE FUNCTION unis_emh.jt_to_topo_geom(
        dst_schema character varying,
        dst_table character varying,
        dst_column character varying,
        geom geometry)
     RETURNS topogeometry
     LANGUAGE 'plpgsql'
     COST 100
     VOLATILE PARALLEL UNSAFE
AS $BODY$
DECLARE
        layer_ layer;
        topology_ topology;
BEGIN
        -- get names
        SELECT * FROM FindLayer(dst_schema, dst_table, dst_column) INTO layer_;
        SELECT * FROM FindTopology((layer_).topology_id) INTO topology_;

        -- insert geometry, no duplicate protection
        RETURN toTopoGeom(geom, (topology_).name, (layer_).layer_id);
END;
$BODY$;

Database log:

2025-06-17 17:41:46.509 CET [2414906] LOG:  server process (PID 2415005)
was terminated by signal 11: Segmentation fault
2025-06-17 17:41:46.509 CEST [2414906] DETAIL:  Failed process was
running: INSERT INTO "j_pmh_topo_geometrie" ("id_geometrie", "topo_geom")
                                     SELECT "id_geometrie",
"unis_emh"."jt_to_topo_geom"(current_schema::text,
'j_pmh_topo_geometrie', 'topo_geom', "geom")
                                     FROM "j_pmh_geometrie"
                                     WHERE "id_geometrie"=63855
2025-06-17 17:41:46.509 CEST [2414906] LOG:  terminating any other
active server processes
2025-06-17 17:41:46.513 CEST [2414906] LOG:  all server processes
terminated; reinitializing
2025-06-17 17:41:46.625 CEST [2415006] LOG:  database system was
interrupted; last known up at 2025-06-17 17:40:42 CEST
2025-06-17 17:41:46.896 CEST [2415006] LOG:  database system was not
properly shut down; automatic recovery in progress
2025-06-17 17:41:46.917 CEST [2415006] LOG:  redo starts at 14F/64BCDA20
2025-06-17 17:41:46.927 CEST [2415006] LOG:  unexpected pageaddr
14F/20000000 in log segment 000000010000014F00000065, offset 0
2025-06-17 17:41:46.927 CEST [2415006] LOG:  redo done at 14F/64FFFFC0
system usage: CPU: user: 0.00 s, system: 0.00 s, elapsed: 0.01 s
2025-06-17 17:41:47.021 CEST [2414906] LOG:  database system is ready to
accept connections

MS.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/postgis-users/attachments/20250618/20824f34/attachment.htm>