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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Hi Peter,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">One further thing you could try, if not already done, is to create Spatial Index’s.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">You can do this within QGIS under the
<b>Layer Properties</b>, by going to the <b>Source</b> tab and selecting, <b>Create Spatial Index</b>.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">See:
<a href="https://medium.com/@wherelytics/understanding-spatial-indexes-in-ogc-geopackage-files-9960fdf71f82">
https://medium.com/@wherelytics/understanding-spatial-indexes-in-ogc-geopackage-files-9960fdf71f82</a>
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Hope this helps<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Richard.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Qgis-user <qgis-user-bounces@lists.osgeo.org>
<b>On Behalf Of </b>Peter Cornelissen<br>
<b>Sent:</b> 14 August 2020 00:19<br>
<b>To:</b> rdmailings@duif.net<br>
<b>Cc:</b> qgis-user@lists.osgeo.org<br>
<b>Subject:</b> Re: [Qgis-user] Adding layer slows down QGIS dramatically after adding a layer<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-family:"Arial",sans-serif">Hi Richard<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial",sans-serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial",sans-serif">Thanks for the suggestion. They are plain filters and I tried indexing every table, but unfortunately it has made no noticeable difference.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial",sans-serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial",sans-serif">Regards, Peter<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On Thu, 13 Aug 2020 at 15:35, Richard Duivenvoorde <<a href="mailto:rdmailings@duif.net" target="_blank">rdmailings@duif.net</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal">On 8/13/20 3:57 PM, Peter Cornelissen wrote:<br>
> Hi<br>
> <br>
> I am using a Geopackage with about 15 tables (a mixture of lines, polygons and points), but each of these tables are<br>
> used 40 or 50 times with filters as many of the elements are used on multiple layers.<br>
> However, I am now finding that as soon as I add a new layer QGIS slows down<br>
> and it is taking 60 seconds or more to do almost any action that involves<br>
> redrawing (zoom in/out/ pan etc) or even moving a layer within the layers<br>
> panel. If I save the project, close down QGIS and restart, it is fine again<br>
> until the next time.<br>
> <br>
> Any suggestions?<br>
> <br>
> Thanks, Peter<br>
<br>
Looking at the attributes which are used in the filters, add 'indexes' too the tables in the Geopackage?
<br>
<br>
In QGIS you can do that by creating a connection to the gpkg with DataBase Manager and then:<br>
'edit table' > tab indexes, > add index<br>
<br>
A geopackage is a sqlite database, so if you have some sql-client (DB-manager, DB-browser) you can fire the create index query there:<br>
CREATE INDEX "foo_index" ON "mygeopackage" ("foo_column")<br>
<br>
Note that these are plain indexes, no spatial ones.<br>
IF your filters are spatial filters, then off course you need spatial indexes.<br>
<br>
HTH<br>
<br>
Regards,<br>
<br>
Richard Duivenvoorde<o:p></o:p></p>
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