Hi list -
I've done some experiments with a dataset consisting of 440000 rows and uploaded this to two database servers: Postgres and SQLServer. Both tables has indexes on Primary key and the spatial column. And then connected to both tables in QGIS. The SQL server is *3 times* slower in retrieving the dataset than Postgres in QGIS! And it's not SQL server's fault!! I've made the same experiment using GeoServer as a client where Postgres is only slightly faster. To make matters worse... In QGIS you can connect to the SQL server database using the "Layer" > "Add Layer" > "Add Vector layer" - i.e. using the OGR driver - to connect to the SQL Server table. This makes the retrieval of SQL Server data nearly as fast as Postgres. I have to conclude, that the native QGIS SQLServer driver is really, really bad. What's the matter with this driver? I recollect, doing the same experiment in QGIS 2.x, that a simple fetch of SQL server data was nearly as fast as retrieving data from a comparable Postgres database server (I’m not talking about complex spatial queries, where Postgres blows SQL Server totally out of the water, but simple retrieval of layer data using a MBR search) Unfortunately, I can't just switch to the OGR driver since I have some write issues with this driver. What gives ??? -- Med venlig hilsen Bo Victor Thomsen
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