Hi,
I can confirm long detection times when connecting to Postgres (~ 25
seconds) using QGIS 1.8.0 compared to 1.7.4. I have some 50 schemas with
both, tables and views in a PostgreSQL 8.4 db. Most tables contain only
several hundred to several thousand features.
It seems QGIS 1.8 scans all views not registered in geometry_columns for
their geometry type like that: SELECT DISTINCT CASE WHEN
upper(geometrytype("the_geom")) IN
('POINT','MULTIPOINT','POINTM','MULTIPOINTM') THEN 'POINT' WHEN
upper(geometrytype("the_geom")) IN
('LINESTRING','MULTILINESTRING','LINESTRINGM','MULTILINESTRINGM') THEN
'LINESTRING' WHEN upper(geometrytype("the_geom")) IN
('POLYGON','MULTIPOLYGON','POLYGONM','MULTIPOLYGONM') THEN 'POLYGON'
END, srid("the_geom") FROM "schema"."view"
So if I tick "Only look in geometry_columns table" for the connection
connecting takes 1 to 2 seconds! I assume that the same can be achieved
by adding all views to geometry_columns.
QGIS 1.7 scanned like that: select distinct case when
upper(geometrytype("the_geom")) IN ('POINT','MULTIPOINT') THEN 'POINT'
when upper(geometrytype("the_geom")) IN ('LINESTRING','MULTILINESTRING')
THEN 'LINESTRING' when upper(geometrytype("the_geom")) IN
('POLYGON','MULTIPOLYGON') THEN 'POLYGON' end from (select "the_geom"
from "schema"."view" where "the_geom" is not null limit 100) as t
Therefore QGIS 1.7.4 loads the view with an sql-query e.g.
"upper(geometrytype("the_geom")) IN ('POLYGON','MULTIPOLYGON')" whereas
1.8 does not. So 1.7 only checked 100 features and detected their
geometry type and made sure that only fitting types are loaded by
setting an appropriate query.
Also QGIS 1.7 offered the possibility to already open a schema while
still detecting. The type said "waiting" for the views in question but
you could nevertheless load a layer where the geometry type was already
detected (e.g. because it is registered in geometry_columns).
Could one of the devs explain why this was changed?
Bernhard
Am 19.07.2012 10:17, schrieb Andre Joost:
Am 19.07.12 10:09, schrieb Giovanni Manghi:
On Thu, 2012-07-19 at 07:14 +0200, [email protected] wrote:
Hallo
‚add postgis layers“ is very, very slowly in qgis 1.80 when I have
many tables. It needs several (up to 10) minutes until all tables
where “detecting” every time when I want add a postgis layer.
Thanks for tricky tips to make it faster!
Hi,
I have DB with 10000+ tables (no views for now) in it and many different
schemas, and the table list shows in a just 2/3 seconds.
Not quiet the same for me:
I use a postgis database with openstreetmap data of my region. The table
for (multi-)polygons takes a lot of time to detect the type of elements.
Only one table, but lots of elements in there (one for every building...)
Greetings,
Andre Joost
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