I am trying to get a handle on importing layers into qgis 2.6 using the "Add MSSQL Spatial Layer" option. I was able to import a layer successfully, but it seems to take a long time to render. Is there a way to handle layers from a database more efficiently? Are there plugins that you would recommend? Also, would it be better to use a Postgres server and add "PostGIS Layers" as opposed to what is being done now, which is adding mssql spatial layers through an Azure DB connection?
Hi have you tried adding a spatial index to your DB? to add a spatial index : Docs
After if the vector layer has a important number of elements, you can choose to display your objects depending on the level of zoom:
In layerProperties -> General