Opened 15 years ago
Closed 15 years ago
#241 closed defect (fixed)
ST_LineCrossingDirection Server Crash (Segfault)
Reported by: | batzee | Owned by: | robe |
---|---|---|---|
Priority: | critical | Milestone: | PostGIS 1.4.1 |
Component: | postgis | Version: | 1.4.X |
Keywords: | segfault | Cc: |
Description
Table definition:
Spalte | Typ | Attribute -------------+------------------------+---------------------------------------------------------------- timeline_id | integer | not null default nextval('timeline_timeline_id_seq'::regclass) name | character varying(64) | not null shortname | character varying(16) | not null theline | geometry | visible | boolean | not null default false country_id | integer | comment | character varying(256) | Indexe: »timeline_pkey« PRIMARY KEY, btree (timeline_id) »unq_name« UNIQUE, btree (name) »unq_shortname« UNIQUE, btree (shortname) Check-Constraints: »enforce_dims_theline« CHECK (ndims(theline) = 2) »enforce_geotype_theline« CHECK (geometrytype(theline) = 'LINESTRING'::text OR theline IS NULL) »enforce_srid_theline« CHECK (srid(theline) = (-1)) Fremdschlüssel-Constraints: »timeline_country_id_fkey« FOREIGN KEY (country_id) REFERENCES country(country_id)
Query:
select name,st_linecrossingdirection(theline, GeomFromText('LINESTRING(2 53.54,20 53.54)')) from mytable;
Output in PSQL client:
server closed the connection unexpectedly This probably means the server terminated abnormally before or while processing the request. Lost connection to server. Trying to Reset: Failed. !>
Output in server logfile (sorry for German..):
2009-08-18 18:30:58 CEST ANWEISUNG: select * from timeline where st_linecrossingdirection(theline, GeomFromText('LINESTRING(8 53.54,11 53.54)')); 2009-08-18 18:31:42 CEST LOG: Serverprozess (PID 16539) wurde von Signal 11 beendet: Segmentation fault 2009-08-18 18:31:42 CEST LOG: aktive Serverprozesse werden abgebrochen 2009-08-18 18:31:42 CEST FATAL: das Datenbanksystem ist im Wiederherstellungsmodus 2009-08-18 18:31:42 CEST LOG: alle Serverprozesse beendet; initialisiere neu
Change History (13)
comment:1 by , 15 years ago
comment:2 by , 15 years ago
It seems the crash is not directly related to a geometry, or at least I cannot find it. The query crashes with every offset >74.
Table size is 125.
It even crashes with offset 100000.
follow-up: 7 comment:3 by , 15 years ago
Can you just dump and attach the table then? I need to create the crash on my own machine in order to debug it.
comment:4 by , 15 years ago
Paul,
I can make my server crash with this
SELECT sum(ST_LineCrossingDirection(a.the_geom, b.the_geom)) FROM ((SELECT ST_MakeLine(ST_Point(i,j),ST_Point(j,i)) As the_geom
FROM generate_series(-10,100,5) As i
CROSS JOIN generate_series(5,70, 4) As j WHERE NOT(i = j) ORDER BY i, i*j)) As a CROSS JOIN
((SELECT ST_MakeLine(ARRAY[ST_Point(i,j),ST_Point(j,i), ST_Point(k,i), ST_Point(j,k)]) As the_geom
FROM generate_series(-10,10000,1500) As i
CROSS JOIN generate_series(5,800, 7) As j CROSS JOIN generate_series(0,800, 200) As k WHERE NOT(i = j) AND NOT (j = k) AND NOT (k = i) ORDER BY i, i*j)) As b
WHERE ST_LineCrossingDirection(a.the_geom,ST_GeomFromText('LINESTRING(8 53.54,11 53.54)')) = 1
I could probably have come up with a simpler statement . It appears to be the use in where condition. Without that it works fine.
comment:5 by , 15 years ago
Owner: | changed from | to
---|---|
Status: | new → assigned |
On closer inspection. I think its how we are freeing constant geometries that is the problem. Only seems to happen if I introduce a constant.
For example this crashes too.
SELECT sum(ST_LineCrossingDirection(a.the_geom, ST_GeomFromText('LINESTRING(1 2,3 4)'))) FROM ((SELECT ST_MakeLine(ST_Point(i,j),ST_Point(j,i)) As the_geom
FROM generate_series(-10,50,10) As i
CROSS JOIN generate_series(40,70, 15) As j WHERE NOT(i = j) ORDER BY i, i*j) ) As a
comment:6 by , 15 years ago
Owner: | changed from | to
---|---|
Status: | assigned → new |
comment:7 by , 15 years ago
Replying to pramsey:
Can you just dump and attach the table then? I need to create the crash on my own machine in order to debug it.
I can send it to you as a PM. Attaching the data to a public forum is not possible, sorry. Pls let me know your e-mail address if you still need the dump. Mine is post at bastian minus voigt dot de
comment:8 by , 15 years ago
I took a quick look at Reginas example. The crash only appears when there is more than one row. If I make a table like
create table c as SELECT ST_MakeLine(ST_Point(-10,40),ST_Point(40,-10)) As the_geom ; insert into c SELECT ST_MakeLine(ST_Point(0,40),ST_Point(40,0)) As the_geom ;
then this crashes:
SELECT sum(ST_LineCrossingDirection(the_geom, ST_GeomFromText('LINESTRING(1 2,3 4)'))) FROM c
it also crashes if I run:
SELECT sum(ST_LineCrossingDirection(the_geom, ST_GeomFromText('LINESTRING(1 2,3 4)'))) FROM c limit 1;
But it will not crash if I run:
SELECT sum(ST_LineCrossingDirection(the_geom, ST_GeomFromText('LINESTRING(1 2,3 4)'))) FROM (select * from c limit 1) d
I don't know enough to understand the internal difference between the two last examples. As I understand it it doesn't wich one of the two rows I put first in the last example so it isn't the lines in itself that crashes the function, but something hangeing there from the last run of the function.
/Nicklas
comment:9 by , 15 years ago
I can just add that I tried the above with two identical rows in the table like
create table c as SELECT ST_MakeLine(ST_Point(-10,40),ST_Point(40,-10)) As the_geom ; insert into c SELECT ST_MakeLine(ST_Point(-10,40),ST_Point(40,-10)) As the_geom ;
with the same result. it doesn't crash with:
SELECT sum(ST_LineCrossingDirection(the_geom, ST_GeomFromText('LINESTRING(1 2,3 4)'))) FROM (select * from c limit 1) d;
but it crashes with:
SELECT sum(ST_LineCrossingDirection(the_geom, ST_GeomFromText('LINESTRING(1 2,3 4)'))) FROM c;
and:
SELECT sum(ST_LineCrossingDirection(the_geom, ST_GeomFromText('LINESTRING(1 2,3 4)'))) FROM c limit 1;
/Nicklas
comment:10 by , 15 years ago
comment:11 by , 15 years ago
Owner: | changed from | to
---|---|
Status: | new → assigned |
Well it doesn't crash anymore. I get a wonderful answer of -42 when I do this.
SELECT sum(ST_LineCrossingDirection(a.the_geom, b.the_geom)) FROM ((SELECT ST_MakeLine(ST_Point(i,j),ST_Point(j,i)) As the_geom FROM generate_series(-10,100,5) As i CROSS JOIN generate_series(5,70, 4) As j WHERE NOT(i = j) ORDER BY i, i*j)) As a CROSS JOIN ((SELECT ST_MakeLine(ARRAY[ST_Point(i,j),ST_Point(j,i), ST_Point(k,i), ST_Point(j,k)]) As the_geom FROM generate_series(-10,10000,1500) As i CROSS JOIN generate_series(5,800, 7) As j CROSS JOIN generate_series(0,800, 200) As k WHERE NOT(i = j) AND NOT (j = k) AND NOT (k = i) ORDER BY i, i*j)) As b WHERE ST_LineCrossingDirection(a.the_geom,ST_GeomFromText('LINESTRING(8 53.54,11 53.54)')) = 1
But I think there is still a problem.
In our documentation — We still have this example that doesn't behave right
SELECT ST_LineCrossingDirection(foo.line1, foo.line2) As l1_cross_l2 ,
ST_LineCrossingDirection(foo.line2, foo.line1) As l2_cross_l1
FROM (SELECT
ST_GeomFromText('LINESTRING(25 169,89 114,40 70,86 43)') As line1, ST_GeomFromText('LINESTRING(2.99 90.16,71 74,20 140,171 154)') As line2 ) As foo;
(gives me -2, 0)
http://www.postgis.org/documentation/manual-svn/ST_LineCrossingDirection.html
So I'll leave this open for now until we figure out why that is giving the presumably wrong answer.
Can't test the hausdorff one yet since don't have 3.2 compiled in on this box.
comment:12 by , 15 years ago
Yeah; I see exactly the same answers. Unfortunately though, I can't make much sense of the integer constants in the manual to work out what the function *should* actually be doing. Can anyone explain this in more detail? For example, do the LEFT/RIGHT parts refer to spatial position or the order of the input parameters?
ATB,
Mark.
comment:13 by , 15 years ago
Resolution: | → fixed |
---|---|
Status: | assigned → closed |
I'm closing this ticket out. I think the server memory issue is resolved and what is left is an artifact in our questionable card counting strategy. I'll put that in as a separate ticket item.
Can you do a binary search and find the geometry that causes the crash? Use limit and offset to search ½, ¼, 1/8 of the data table until you find the one record that is causing the problem…