[Qgis-user] Qgis - Big Postgis layer - open attribute table takes a life to execute

[Rossin Pietro]

Hello list
I'm facing a problem with qgis (2.14.3)  and postgis multipolygon layer.
This layer is a "big" (2200 records) dataset, with id, geom and other 4 columns ( character varying(n) )
Id is serial primary key and there is an Index on geom using gist.
The dimension of this layer as shp is 17.5MB (16.3 MB shp and 1.2MB dbf)
If I load the shape file in qgis it loads quick and the attribute table too (it has to be so because it's on my filesystem..).
As Postgis layer it takes much longer to load the geometry in TOC but it takes a huge amount of time to open the attribute table.

I took a look at network data transfer between the open attribute data table (not geometry display) and the complete load and 32MB are downloaded.. It takes at least 1 minute to open the table (5 columns, 2173 records) with qgis freezing until load
Then I made a try to union all polygons with same attributes so a layer with 16 rows is generated, same problem , almost 32MB data transfer and a huge time to load the attribute table.

In PgAdmin a select like
SELECT id, field1, field2, field3, field4  FROM mytable;
Takes 700ms to return 2173 records

SELECT DISTINCT field1, field2, field3, field4  FROM mytable;
Takes 42ms to execute and return 16 rows

So, what happens with QGis and attribute data table? It seems that all the table geometry column included is loaded if data attribute is requested...

Is there some setting I miss to setup in preferences?

Thanks
Pietro Rossin

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