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<TITLE>RE: [postgis-users] Large geometry issue</TITLE>
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<!-- Converted from text/plain format -->
<P><FONT SIZE=2>These are some of the ids that the one comparison found:<BR>
<BR>
gex_runtime=# select w.id_as_int from wsc_candidates w, oli_req x WHERE w.geometry && x.bbox AND contains(x.oli_req_geom,w.geometry) AND x.oli_req_id = 114672 order by 1;<BR>
id_as_int<BR>
-----------<BR>
5905594<BR>
5905626<BR>
5905704<BR>
5905705<BR>
5905706<BR>
5905719<BR>
5905725<BR>
5905835<BR>
5905837<BR>
5905838<BR>
5906142<BR>
5906143<BR>
5906146<BR>
5906153<BR>
5906159<BR>
5906159<BR>
5906175<BR>
5906176<BR>
<...><BR>
6139126<BR>
6139417<BR>
6139418<BR>
6139426<BR>
6139427<BR>
(241 rows)<BR>
<BR>
GSW<BR>
<BR>
<BR>
<BR>
-----Original Message-----<BR>
From: postgis-users-bounces@postgis.refractions.net on behalf of Paul Ramsey<BR>
Sent: Thu 7/5/2007 10:29 PM<BR>
To: PostGIS Users Discussion<BR>
Cc: Mark Leslie<BR>
Subject: Re: [postgis-users] Large geometry issue<BR>
<BR>
That is indeed concerning, can you send us the big shape and a few of <BR>
the small shapes that 2.2.3 is turning up as containments and 3.0.0 <BR>
is not?<BR>
<BR>
P<BR>
<BR>
On 5-Jul-07, at 6:11 PM, Gregory Williamson wrote:<BR>
<BR>
> Having has a little time to look at this in detail I can see why <BR>
> this is ugly ... a very long sinuous shape vs a ton of small <BR>
> rectangles, so the bounding box does get a lot of candidates which <BR>
> then have to be winnowed.<BR>
><BR>
> I do find myself wondering at this result:<BR>
><BR>
> POSTGIS="1.2.1" GEOS="3.0.0rc4-CAPI-1.3.3" USE_STATS<BR>
> select count(*) from wsc_candidates w, oli_req x WHERE w.geometry <BR>
> && x.bbox AND contains(x.oli_req_geom,w.geometry) AND x.oli_req_id <BR>
> = 114672;<BR>
> count<BR>
> -------<BR>
> 0<BR>
> (1 row)<BR>
><BR>
> Time: 4347.776 ms<BR>
><BR>
> versus<BR>
> POSTGIS="1.2.1" GEOS="2.2.3-CAPI-1.1.1" PROJ="Rel. 4.4.9, 29 Oct <BR>
> 2004" USE_STATS<BR>
> # select count(*) from wsc_candidates w, oli_req x WHERE w.geometry <BR>
> && x.bbox AND contains(x.oli_req_geom,w.geometry) AND x.oli_req_id <BR>
> = 114672;<BR>
> count<BR>
> -------<BR>
> 241<BR>
> (1 row)<BR>
><BR>
> Time: 15956.425 ms<BR>
><BR>
> Not the time so much -- the box is a bit older -- but the disparity <BR>
> in rows. 241 seems more likely from eyeballing the data in JUMP ... <BR>
> or have I overlooked something obvious ?<BR>
><BR>
> Thanks,<BR>
><BR>
> Greg W.<BR>
><BR>
><BR>
> -----Original Message-----<BR>
> From: postgis-users-bounces@postgis.refractions.net on behalf of <BR>
> Martin Davis<BR>
> Sent: Thu 7/5/2007 5:32 PM<BR>
> To: PostGIS Users Discussion<BR>
> Subject: Re: [postgis-users] Large geometry issue<BR>
><BR>
> No problem. Actually it's me being blind - I just saw the attachment<BR>
> with the test data.<BR>
><BR>
> 2530 vertices isn't a very big polygon. So this isn't a problem with<BR>
> lots of holes or shells, it simply reveals that we're not <BR>
> extracting the<BR>
> maximum possible performance from a querying involving comparing many<BR>
> small geoms against a single large one. Stay tuned - hopefully we'll<BR>
> have a better story for this shortly.<BR>
><BR>
> Martin<BR>
><BR>
> Gregory Williamson wrote:<BR>
> ><BR>
> > Martin,<BR>
> ><BR>
> > Sorry for the lack of coherence -- 2530 vertices in this test <BR>
> polygon<BR>
> > ... it should be in the original posting I sent, an attached zip <BR>
> file<BR>
> > with two tables; this is the single entry in the oli_req table. The<BR>
> > other table has some 13000 rows of polygons which are either<BR>
> > completely within or overlapping with the large poly.<BR>
> ><BR>
> > If you can't get at that let me know and I'll send you a copy ...<BR>
> ><BR>
> > Greg W.<BR>
> ><BR>
> ><BR>
> > -----Original Message-----<BR>
> > From: postgis-users-bounces@postgis.refractions.net on behalf of<BR>
> > Martin Davis<BR>
> > Sent: Thu 7/5/2007 5:09 PM<BR>
> > To: PostGIS Users Discussion<BR>
> > Subject: Re: [postgis-users] Large geometry issue<BR>
> ><BR>
> > Greg,<BR>
> ><BR>
> > Can you elaborate on your statement "2530 in a sinlge polygon"? <BR>
> Do you<BR>
> > mean holes or subPolygons in a MultiPolygon?<BR>
> ><BR>
> > Either way, currently JTS is not optimized for working with very <BR>
> large<BR>
> > numbers of holes and sub-polygons. As Paul says, we are currently<BR>
> > working on improving this. Hopefully we can at least match the<BR>
> > performance of the Other DMBS(es) for this situation!<BR>
> ><BR>
> > Would it be possible for me to obtain this geometry for testing?<BR>
> ><BR>
> > Martin<BR>
> ><BR>
> ><BR>
> ><BR>
> > Gregory Williamson wrote:<BR>
> > ><BR>
> > > Dear peoples,<BR>
> > ><BR>
> > > I have a problem with a query that uses an absurdly large geometry<BR>
> > > (2530 in a single polygon). This is srid -1 (part of a large <BR>
> test of<BR>
> > > postgres vs some other database product). Everything has been <BR>
> vacuumed<BR>
> > > and analyzed.<BR>
> > ><BR>
> > > The initial search to find candidates in a target table is <BR>
> quite fast:<BR>
> > > catest=# select count(*) from wtm_sub_cell w, order_line_item x <BR>
> WHERE<BR>
> > > x.bbox && w.geometry AND x.id_as_int = 114672;<BR>
> > > count<BR>
> > > -------<BR>
> > > 13168<BR>
> > > (1 row)<BR>
> > ><BR>
> > > Time: 9.472 ms<BR>
> > ><BR>
> > > Trying to get the list narrowed to geometries that are completely<BR>
> > > contained by the requested shape is slow:<BR>
> > > catest=# select count(*) from wtm_sub_cell w, order_line_item x <BR>
> WHERE<BR>
> > > x.bbox && w.geometry AND distance(x.geometry,w.geometry) = 0 and<BR>
> > > x.id_as_int = 114672;<BR>
> > > count<BR>
> > > -------<BR>
> > > 1112<BR>
> > > (1 row)<BR>
> > ><BR>
> > > Time: 69277.780 ms<BR>
> > ><BR>
> > > So I have two questions:<BR>
> > > a) anything better to use than "distance(x,y) = 0) ? I tried<BR>
> > > st_within -- it is about the same speed but returns no polys, <BR>
> which is<BR>
> > > strange to me, but I also haven't looked at these in detail <BR>
> yet. For<BR>
> > > example:<BR>
> > > catest=# select count(*) from wtm_sub_cell w, order_line_item x <BR>
> WHERE<BR>
> > > x.bbox && w.geometry AND st_within(x.geometry,w.geometry) and<BR>
> > > x.id_as_int = 114672;<BR>
> > > count<BR>
> > > -------<BR>
> > > 0<BR>
> > > (1 row)<BR>
> > ><BR>
> > > Time: 1173.185 ms<BR>
> > > (same results with st_within(w.geometry,x.geometry):<BR>
> > > catest=# select count(*) from wtm_sub_cell w, order_line_item x <BR>
> WHERE<BR>
> > > x.bbox && w.geometry AND st_within(w.geometry,x.geometry) and<BR>
> > > x.id_as_int = 114672;<BR>
> > > count<BR>
> > > -------<BR>
> > > 0<BR>
> > > (1 row)<BR>
> > ><BR>
> > ><BR>
> > > b) anything I can do to speed things up ? I have tried <BR>
> boosting work<BR>
> > > mem to 16 megs (from 1) and it made no apparent difference.<BR>
> > ><BR>
> > ><BR>
> > ><BR>
> > > I have a self contained test case that shows the same behavior <BR>
> -- the<BR>
> > > one large poly and all the candidates in another table. <BR>
> Apologies for<BR>
> > > the size; hopefully it's not been mangled in the transfers.<BR>
> > ><BR>
> > > Explain analyze of the sample (the sequential is sensible since <BR>
> there<BR>
> > > is only one row in the table):<BR>
> > > catest=# explain analyze select count(*) from wsc_candidates w,<BR>
> > > oli_req x WHERE w.geometry && x.bbox AND<BR>
> > > distance(w.geometry,x.oli_req_geom) > 0 AND x.oli_req_id = 114672;<BR>
> > ><BR>
> > > QUERY PLAN<BR>
> > ><BR>
> > <BR>
> ----------------------------------------------------------------------<BR>
> ----------------------------------------------------------------------<BR>
> -----------<BR>
> > > Aggregate (cost=20.28..20.29 rows=1 width=0) (actual<BR>
> > > time=77232.858..77232.859 rows=1 loops=1)<BR>
> > > -> Nested Loop (cost=0.00..9.30 rows=4389 width=0) (actual<BR>
> > > time=6.389..77221.506 rows=12056 loops=1)<BR>
> > > Join Filter: (distance(w.geometry, x.oli_req_geom) ><BR>
> > > 0::double precision)<BR>
> > > -> Seq Scan on oli_req x (cost=0.00..1.01 rows=1<BR>
> > > width=40602) (actual time=0.007..0.009 rows=1 loops=1)<BR>
> > > Filter: (oli_req_id = 114672)<BR>
> > > -> Index Scan using wsc_c_spatial_ndx on <BR>
> wsc_candidates w<BR>
> > > (cost=0.00..8.27 rows=1 width=109) (actual time=0.022..25.991<BR>
> > > rows=13168 loops=1)<BR>
> > > Index Cond: (w.geometry && x.bbox)<BR>
> > > Filter: (w.geometry && x.bbox)<BR>
> > > Total runtime: 77232.901 ms<BR>
> > > (9 rows)<BR>
> > ><BR>
> > > Time: 77233.773 ms<BR>
> > ><BR>
> > ><BR>
> > > And for the real thing:<BR>
> > > catest=# explain analyze select count(*) from wtm_sub_cell w,<BR>
> > > order_line_item x WHERE w.geometry && x.bbox AND<BR>
> > > distance(w.geometry,x.geometry) = 0 AND x.id_as_int = 114672;<BR>
> > <BR>
> > <BR>
> QUERY<BR>
> > > PLAN<BR>
> > ><BR>
> > <BR>
> ----------------------------------------------------------------------<BR>
> ----------------------------------------------------------------------<BR>
> > > Aggregate (cost=141.83..141.84 rows=1 width=0) (actual<BR>
> > > time=77457.587..77457.588 rows=1 loops=1)<BR>
> > > -> Nested Loop (cost=5.99..141.83 rows=1 width=0) (actual<BR>
> > > time=15.682..77456.541 rows=1112 loops=1)<BR>
> > > Join Filter: (distance(w.geometry, x.geometry) = <BR>
> 0::double<BR>
> > > precision)<BR>
> > > -> Index Scan using oli_id_ndx on order_line_item x<BR>
> > > (cost=0.00..8.30 rows=1 width=383) (actual time=0.012..0.018 <BR>
> rows=1<BR>
> > > loops=1)<BR>
> > > Index Cond: (id_as_int = 114672)<BR>
> > > -> Bitmap Heap Scan on wtm_sub_cell w <BR>
> (cost=5.99..132.97<BR>
> > > rows=32 width=109) (actual time=2.988..21.796 rows=13168 loops=1)<BR>
> > > Filter: (w.geometry && x.bbox)<BR>
> > > -> Bitmap Index Scan on wsc_geom_idx1<BR>
> > > (cost=0.00..5.98 rows=32 width=0) (actual time=2.828..2.828 <BR>
> rows=13168<BR>
> > > loops=1)<BR>
> > > Index Cond: (w.geometry && x.bbox)<BR>
> > > Total runtime: 77457.633 ms<BR>
> > > (10 rows)<BR>
> > ><BR>
> > > Time: 77458.458 ms<BR>
> > ><BR>
> > ><BR>
> > > The tables involved by size:<BR>
> > > catest=# select count(*) from wsc_candidates;<BR>
> > > count<BR>
> > > -------<BR>
> > > 13168<BR>
> > > (1 row)<BR>
> > ><BR>
> > > Time: 2.586 ms<BR>
> > > catest=# select count(*) from oli_req;<BR>
> > > count<BR>
> > > -------<BR>
> > > 1<BR>
> > > (1 row)<BR>
> > ><BR>
> > > Time: 0.193 ms<BR>
> > > catest=# select count(*) from wtm_sub_cell;<BR>
> > > count<BR>
> > > ---------<BR>
> > > 6399928<BR>
> > > (1 row)<BR>
> > ><BR>
> > > Time: 1776.508 ms<BR>
> > > catest=# select count(*) from order_line_item;<BR>
> > > count<BR>
> > > --------<BR>
> > > 395921<BR>
> > > (1 row)<BR>
> > ><BR>
> > > Time: 176.083 ms<BR>
> > ><BR>
> > ><BR>
> > > Many thanks for your time and bandwidth!<BR>
> > ><BR>
> > > Greg Williamson<BR>
> > > Senior DBA<BR>
> > > GlobeXplorer LLC, a DigitalGlobe company<BR>
> > ><BR>
> > > Confidentiality Notice: This e-mail message, including any<BR>
> > > attachments, is for the sole use of the intended recipient(s) <BR>
> and may<BR>
> > > contain confidential and privileged information and must be <BR>
> protected<BR>
> > > in accordance with those provisions. Any unauthorized review, use,<BR>
> > > disclosure or distribution is prohibited. If you are not the <BR>
> intended<BR>
> > > recipient, please contact the sender by reply e-mail and <BR>
> destroy all<BR>
> > > copies of the original message.<BR>
> > ><BR>
> > > (My corporate masters made me say this.)<BR>
> > ><BR>
> > > <BR>
> ----------------------------------------------------------------------<BR>
> --<BR>
> > ><BR>
> > > _______________________________________________<BR>
> > > postgis-users mailing list<BR>
> > > postgis-users@postgis.refractions.net<BR>
> > > <A HREF="http://postgis.refractions.net/mailman/listinfo/postgis-users">http://postgis.refractions.net/mailman/listinfo/postgis-users</A><BR>
> > ><BR>
> ><BR>
> > --<BR>
> > Martin Davis<BR>
> > Senior Technical Architect<BR>
> > Refractions Research, Inc.<BR>
> > (250) 383-3022<BR>
> ><BR>
> > _______________________________________________<BR>
> > postgis-users mailing list<BR>
> > postgis-users@postgis.refractions.net<BR>
> > <A HREF="http://postgis.refractions.net/mailman/listinfo/postgis-users">http://postgis.refractions.net/mailman/listinfo/postgis-users</A><BR>
> ><BR>
> > <BR>
> ----------------------------------------------------------------------<BR>
> --<BR>
> ><BR>
> > _______________________________________________<BR>
> > postgis-users mailing list<BR>
> > postgis-users@postgis.refractions.net<BR>
> > <A HREF="http://postgis.refractions.net/mailman/listinfo/postgis-users">http://postgis.refractions.net/mailman/listinfo/postgis-users</A><BR>
> ><BR>
><BR>
> --<BR>
> Martin Davis<BR>
> Senior Technical Architect<BR>
> Refractions Research, Inc.<BR>
> (250) 383-3022<BR>
><BR>
> _______________________________________________<BR>
> postgis-users mailing list<BR>
> postgis-users@postgis.refractions.net<BR>
> <A HREF="http://postgis.refractions.net/mailman/listinfo/postgis-users">http://postgis.refractions.net/mailman/listinfo/postgis-users</A><BR>
><BR>
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