Bug report #7883
Large MSSQL Tables Very Slow To Open
|Affected QGIS version:||master||Regression?:||No|
|Operating System:||Easy fix?:||No|
|Pull Request or Patch supplied:||No||Resolution:|
|Crashes QGIS or corrupts data:||No||Copied to github as #:||16757|
There is a major delay when adding large, detailed MSSQL maps in QGIS. I have a 500MB+ contour file that loads in less than 1 second in MapServer & MapInfo Pro but QGIS appears to be doing some sort of full scan whenever the table is added via the "Add MSSQL" DB tool or when loading as part of a project.
Once the file is loaded, it renders fine but the delay when opening is a major issue. Loading projects containing lots of regular MSSQL spatial layers is also seems slower than it should be presumably due to the same issue.
I have not yet tested similar files in PostGIS.