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