QGIS » QGIS Application

When opening attribute tables of larger data sets, QGIS opens a dialogue displaying the number of features loaded, takes a long time to load all the features, and consumes abnormal amounts of memory (~1.1GB) in the process (see attached screenshot). During this time, QGIS is otherwise unusable. The dataset size is 4.7 million features with 40 or so fields (2.1GB attribute table as a DBF). I have reproduced this problem with the same dataset as a shapefile, file geodatabase feature class, and PostGIS table. For PostGIS, I used PostgreSQL 9.4 x64 and PostGIS 2.1 on a local database stored on an SSD, with maintenance queries and spatial indices built.Performing attribute queries and spatial selections based on PostGIS geometries is also very slow.

PS; On an unrelated note, I've also noted very slow performance with the PostGIS raster driver when using raster2pgsql to import indexed and tiled rasters. I would be willing to file and document a second bug report on this issue but I think it has been previously reported.