Thank you, Jürgen. > PostgreSQL-Users probably don't use OGR to access the database - > same for SpatiaLite, Oracle or MSSQL users. Right - there are no problems when connecting with the native QGIS provider for PostgreSQL. What are the chances that MySQL also gets native QGIS support that bypasses OGR?
> QGIS does multithreaded rendering and because OGR layers are not > thread safe the OGR provider always reopens the layer on every > rendering run. Apparently that's not too expensive for file based > data sources, which I think the OGR provider is mostly used for. The described OGR problem emerged with QGIS 2.0. Was that version already influenced with multithreaded rendering? Anyway, it is not only that the OGR provider reopens the layer on every rendering run. It is instructed by QGIS to reopen SEPARATELY every record of that layer and query it with all tables in the database on every rendering run. So instead of simple "connect->select * from table...->quit" the server will be flooded with literally thousands of reopenings that cause QGIS to freeze for minutes (queries = number of records in the table multiplied by number of tables in the database). I am not sure what part of this behavior is intended in order to make the OGR provider thread-safe and what is a bug? I can get rid of the unnecessary querries of all tables with manually modifying the layer connection settings in the .qgs file. But I do not know how to get rid of reopenings for each record separately. Shall I file a ticket? Pavol _______________________________________________ Qgis-developer mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/qgis-developer
