Hi Jonathan
Thanks for those tips that helped a lot, it also helped that I removed some records from the user_sdo_geom_metadata table that were related to some excessively large views as this was impacting upon the speed of QGIS assessing all of the layers - it now works perfectly! Thanks again Steve From: Jonathan Moules [mailto:[email protected]] Sent: 12 July 2013 11:27 To: Steven Campbell Cc: Nathan Woodrow; qgis-user Subject: Re: [Qgis-user] OS Mastermap, SQL Server and QGIS Hi Steve, As an aside, do you know if the Oracle connector uses the user_sdo_geom_metadata table to identify the SRID and extents of the tables? Not that particular table, not for extents (not sure about SRID). There are various options for the connector which make things much faster. >From the help: * Only look in meta data table Restricts the displayed tables to those that are in the all_sdo_geom_metadata view. This can speed up the initial display of spatial tables. * Use estimated table statistics for the layer metadata Whenthe layer is setup various metadata is required for the Oracle table. Thisincludes information such as the table row count, geometry type and spatialextents of the data in the geometry column. If the table contains a largenumber of rows determining this metadata is time consuming. By activating thisoption the following fast table metadata operations are done: Row count isdetermined from all_tables.num_rows. Table extents are always determined withthe SDO_TUNE.EXTENTS_OF function even if a layer filter is applied. The tablegeometry is determined from the first 100 non-null geometry rows in the table. Those two in particular speed things up. Jonathan On 11 July 2013 16:19, Steven Campbell <[email protected]> wrote: Hi Nathan Thanks for making the change - it is sooo much quicker now to load, especially for such a large dataset as Mastermap! Just a quick question though, if I try to connect to a secondary MSSQL database, it takes a very long time to find the tables. Generally what I do is I open a boundary file table (stored in one MSSQL table) so I can zoom in to a small location, and then go to open my Mastermap but the initial time taken by QGIS to detect the Mastermap table takes a considerable time - once found it is quick to open, pan etc - it's just the initial connection that seems very slow. As an aside, do you know if the Oracle connector uses the user_sdo_geom_metadata table to identify the SRID and extents of the tables? Thanks again! Steve From: Nathan Woodrow [mailto:[email protected]] Sent: 02 July 2013 04:02 To: Steven Campbell Cc: qgis-user Subject: Re: [Qgis-user] OS Mastermap, SQL Server and QGIS Hey Steven, I have made the change in master now too allow QGIS too look in the spatial index table for faster extent loading. Works like a treat. I would still have the geometry_columns table to allow QGIS to find the tables quicker but you don't need the max_x, etc stuff. Thanks for the tip. Regards, Nathan On Sat, Jun 29, 2013 at 12:00 AM, Steven Campbell <[email protected]> wrote: Hi Does anyone else have significant time delays when trying to open large datasets from a SQL database in QGIS? I have uploaded my Ordnance survey MasterMap data (coverage is the size of an average English County) and although the initial connection to identify the table is very quick, the loading of the table (even when zoomed in to a very big scale (i.e. 1:100) it takes a very long time to open. Once opened the speed is very quick, but getting it to open takes a lot of patience as the application appears to hang. On a slightly related topic, if I have connected to one MSSQL database, QGIS then struggles if I try to connect to an additional database, again it just appears to hang for a considerable period of time (30 minutes or more at times), it seems odd especially as the connection to the first SQL database is almost instant.... Any suggestions as to how I can improve this speed would be greatly appreciated. Thanks Steve Campbell GIS Manager Corporate Strategy and Communications Borough of Poole | Civic Centre | Poole BH15 2RU Tel: 01202 633 362 Email: [email protected] Website:www.boroughofpoole.com <http://www.boroughofpoole.com/> Think Green! Please Recycle DISCLAIMER: This email and any files transmitted with it may be confidential, legally privileged and protected in law and are intended solely for the use of the individual to whom it is addressed. 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