I'm forwarding this mail from -user as it didn't get attention there
yesterday. Today I've tried again a v.out.postgis -l, this time
with a different (bigger) dataset.
This other dataset took 20 minutes to import/build, and took 85 minutes
to export to PostGIS (4 times more expensive to export).
v.out.postgis complete. 224655 primitives written to <grass_ulfareale>.
real 85m16.237s
user 2m48.962s
sys 1m19.671s
Is the export doing anything else than INSERT calls ?
I've seen some UPDATE calls against edges (which could maybe be avoided,
same problem in PostGIS itself: http://trac.osgeo.org/postgis/ticket/2993;
but I hadn't noticed if GRASS is also calling SELECT against the ISO
topology functions.
The input GRASS map:
nodes=107553
points=0
lines=0
boundaries=158084
centroids=66571
areas=66577
islands=16046
primitives=224655
map3d=0
The created PostGIS topology:
Topology topo_grass_ulfareale (5), SRID 0, precision 0
174124 nodes, 158084 edges, 82623 faces, 0 topogeoms, 1 layers
Layer 1, type Polygonal (3), 0 topogeoms
Deploy: public.grass_ulfareale.topo
The "0 topogeoms" part of the summary reveals a bug somewhere.
It means TopoGeometry objects were not registered in the relation
table. How are them created ? I see literal TopoGeometry objects
present in the public.grass_ulfareale.topo table, but those
numbers have no meaning on themselves w/out corresponding entries
in topo_grass_ulfareale.relation.
--strk;
----- Forwarded message from Sandro Santilli <strk@keybit.net> -----
Date: Wed, 19 Nov 2014 00:17:33 +0100
From: Sandro Santilli <strk@keybit.net>
To: grass-user@lists.osgeo.org
Cc: landa.martin@gmail.com
Subject: v.out.postgis -l running for hours
User-Agent: Mutt/1.5.21 (2010-09-15)
Bcc: sandro.santilli@gmail.com
I've imported a ~1 million small polygons dataset from PostGIS into
GRASS with v.in.ogr, which tool less than 30 minutes and was now
trying to export it into the PostGIS Topology model with v.out.postgis -l.
Unexpectedly this latter step is beeing running for hours and did not
even complete the first part:
GRASS 7.0.0beta3 (world):/usr/src/grass/grass-7.0.0beta3 > time \
v.out.postgis -l input=million_poly_topo1 \
olayer=grass_million_poly_topo1 dsn="PG:dbname=strk" \
olink=pg_million_poly_topo1
Copying features...
35%
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
15997 strk 20 0 4928752 2.069g 1.578g R 98.5 13.3 280:28.46 postgres: strk strk [local] UPDATE
15994 strk 20 0 2796056 2.506g 7432 S 1.6 16.1 10:07.11 v.out.postgis -l input=million_poly_topo1 olayer=grass_million_poly_topo1 dsn+
On the PostgreSQL side there's no data load visible:
strk=# select count(*) from grass_million_poly_topo1;
count
-------
0
(1 row)
strk=# select topologysummary('topo_grass_million_poly_topo1');
topologysummary
--------------------------------------------------------------------
Topology topo_grass_million_poly_topo1 (2405), SRID 0, precision 0+
0 nodes, 0 edges, 0 faces, 0 topogeoms, 1 layers +
Layer 1, type Polygonal (3), 0 topogeoms +
Deploy: public.grass_million_poly_topo1.topo +
(1 row)
I guess things are being done in a transaction ?
From the output table structure it looks like v.out.postgis is also
trying to export simple features (the "geom" field):
strk=# \d grass_million_poly_topo1
Table "public.grass_million_poly_topo1"
Column | Type | Modifiers
--------+-------------------+------------------------------------------------------------------------
fid | integer | not null default nextval('grass_million_poly_topo1_fid_seq'::regclass)
cat | integer |
value | integer |
geom | geometry(Polygon) |
topo | topogeometry |
Indexes:
"grass_million_poly_topo1_pkey" PRIMARY KEY, btree (fid)
"grass_million_poly_topo1_cat_idx" btree (cat)
"grass_million_poly_topo1_geom_idx" gist (geom)
"public_grass_million_poly_topo1_topo_idx" btree (((topo).id))
Check constraints:
"check_topogeom_topo" CHECK ((topo).topology_id = 2405 AND (topo).layer_id = 1 AND (topo).type = 3)
Could that be the cause of the slowness ? Is there a way to disable
conversion to simple-feature, which is already supported by
PostGIS Topology itself ?
Thanks in advance.
--strk;
() Free GIS & Flash consultant/developer
/\ http://strk.keybit.net/services.html
----- End forwarded message -----