<div dir="ltr"><div><div><div>Hi,<br><br></div>I was wondering if these preview jobs are enabled in QGIS Server context, when requesting a GetMap from any client. I am pretty sure the context of the preview jobs execution is related to Desktop, but I would like to be sure.</div><div>Any hint on this ?</div><div><br></div>Regards,<br></div>Michaël<br></div><div class="gmail_extra"><br><div class="gmail_quote">2017-11-16 11:15 GMT+01:00 Matthias Kuhn <span dir="ltr"><<a href="mailto:matthias@opengis.ch" target="_blank">matthias@opengis.ch</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
  
    
  
  <div text="#000000" bgcolor="#FFFFFF">
    <p>Hi Patrick,</p>
    <p>Would be interesting to do this test with previews enabled and
      disabled. Then we'll see if it's actually the previews or some
      other mechanism that is causing this.<br>
    </p>
    <p>IIRC only a composite image is saved in the preview jobs and not
      each layer separately, but that's just what I remember and not
      evidence based.<br>
    </p>
    <p> You can enable them in the python console with</p>
    <p>    iface.mapCanvas().<wbr>setPreviewJobsEnabled(True)</p>
    <p>and disable with</p>
    <p>    iface.mapCanvas().<wbr>setPreviewJobsEnabled(False)</p>
    <p>Thanks for a feedback</p><span class="HOEnZb"><font color="#888888">
    <p>Matthias<br>
    </p></font></span><div><div class="h5">
    <br>
    <div class="m_6208825008050013630moz-cite-prefix">On 11/16/2017 08:42 AM, Patrick Dunford
      wrote:<br>
    </div>
    <blockquote type="cite">
      
      <p>In my current project using Qgis 2.99, turning off the rasters
        uses 16 GB, turning them on uses 52 GB</p>
      <p>I do not believe it is independent from the number of layers
        that are being displayed.</p>
      <p>Previous versions of the software did not cache every single
        raster (the number of rasters actually being displayed on the
        canvas at any one time is a small fraction of the total number
        in the project)</p>
      On 16/11/17 20:11, Matthias Kuhn wrote:<br>
      <blockquote type="cite">
        
        <p>Hi Patrick,</p>
        <p>This uses some memory (~ canvas width pixels * canvas height
          pixels * 8 preview images * 32 bit RGBA), so let's assume 50
          MB to 100 MB.</p>
        <p>This consumption is independent from the number or type of
          layers.</p>
        <p>Matthias<br>
        </p>
        <br>
        <div class="m_6208825008050013630moz-cite-prefix">On 11/16/2017 08:02 AM, Patrick
          Dunford wrote:<br>
        </div>
        <blockquote type="cite">
          
          <p>So to put it another way this is the reason why Qgis wants
            to use a huge amount of memory (40 GB) when I have a lot of
            raster images loaded in the background. <br>
          </p>
          <br>
          <div class="m_6208825008050013630moz-cite-prefix">On 16/11/17 18:56, Tim Sutton
            wrote:<br>
          </div>
          <blockquote type="cite">
            
            Hi<br>
            <div><br>
              <blockquote type="cite">
                <div>On 16 Nov 2017, at 04:35, Patrick Dunford
                  <<a href="mailto:enzedrailmaps@gmail.com" target="_blank">enzedrailmaps@gmail.com</a>>
                  wrote:</div>
                <br class="m_6208825008050013630Apple-interchange-newline">
                <div>
                  <p style="white-space:pre-wrap;font-family:Helvetica;font-size:14px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;word-spacing:0px;background-color:rgb(255,255,255)">What is this "preview job" function?</p>
                  <br style="font-family:Helvetica;font-size:14px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255)">
                </div>
              </blockquote>
              <div><br>
              </div>
              <div>Its application logic to prefetch / pre-render
                offscreen content in anticipation of user panning the
                map.</div>
              <div><br>
              </div>
              <div>Regards</div>
              <div><br>
              </div>
              <div>Tim</div>
              <blockquote type="cite">
                <div><br style="font-family:Helvetica;font-size:14px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255)">
                  <span style="font-family:Helvetica;font-size:14px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);float:none;display:inline!important">______________________________<wbr>_________________</span><br style="font-family:Helvetica;font-size:14px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255)">
                  <span style="font-family:Helvetica;font-size:14px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);float:none;display:inline!important">QGIS-Developer mailing list</span><br style="font-family:Helvetica;font-size:14px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255)">
                  <span style="font-family:Helvetica;font-size:14px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);float:none;display:inline!important"><a href="mailto:QGIS-Developer@lists.osgeo.org" target="_blank">QGIS-Developer@lists.osgeo.org</a></span><br style="font-family:Helvetica;font-size:14px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255)">
                  <span style="font-family:Helvetica;font-size:14px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);float:none;display:inline!important">List info: <a href="https://lists.osgeo.org/mailman/listinfo/qgis-developer" target="_blank">https://lists.osgeo.org/<wbr>mailman/listinfo/qgis-<wbr>developer</a></span><br style="font-family:Helvetica;font-size:14px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255)">
                  <span style="font-family:Helvetica;font-size:14px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);float:none;display:inline!important">Unsubscribe: <a href="https://lists.osgeo.org/mailman/listinfo/qgis-developer" target="_blank">https://lists.osgeo.org/<wbr>mailman/listinfo/qgis-<wbr>developer</a></span></div>
              </blockquote>
            </div>
            <br>
            <div>
              <div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-variant-numeric:normal;font-variant-alternates:normal;font-variant-east-asian:normal;font-weight:normal;letter-spacing:normal;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;line-height:normal;text-align:center"><span>—</span></div>
              <div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-variant-numeric:normal;font-variant-alternates:normal;font-variant-east-asian:normal;letter-spacing:normal;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;line-height:normal;text-align:center">
                <div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:center;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-alternates:normal;font-variant-east-asian:normal;margin:0px;line-height:normal;min-height:14px"><br>
                </div>
                <br class="m_6208825008050013630Apple-interchange-newline" style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:center;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">
                <span style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:center;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span><span><span><span><span><span><span><span><span><img id="m_6208825008050013630D186BD8A-F550-478C-AD02-19C4467B3C21" src="cid:part5.52C184EC.5CBC6674@opengis.ch"></span>
                                  <div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:center;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-alternates:normal;font-variant-east-asian:normal;margin:0px;line-height:normal;min-height:14px"><br class="m_6208825008050013630Apple-interchange-newline">
                                    <br class="m_6208825008050013630Apple-interchange-newline">
                                    <br>
                                  </div>
                                  <div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:center;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-alternates:normal;font-variant-east-asian:normal;margin:0px;line-height:normal;min-height:14px"><br>
                                  </div>
                                  <div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:center;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-alternates:normal;font-variant-east-asian:normal;margin:0px;line-height:normal"><b>Tim Sutton</b></div>
                                  <div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:center;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-alternates:normal;font-variant-east-asian:normal;margin:0px;line-height:normal;min-height:14px"><br>
                                  </div>
                                  <div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:center;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-alternates:normal;font-variant-east-asian:normal;margin:0px;line-height:normal"><b>Co-founder:</b><span class="m_6208825008050013630Apple-converted-space"> </span>Kartoza</div>
                                  <div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:center;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-alternates:normal;font-variant-east-asian:normal;margin:0px;line-height:normal"><b>Project
                                      chair:</b><span style="font-weight:normal"><span class="m_6208825008050013630Apple-converted-space"> </span><a href="http://QGIS.org" target="_blank">QGIS.org</a></span></div>
                                  <div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:center;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-alternates:normal;font-variant-east-asian:normal;margin:0px;line-height:normal;min-height:14px"><br>
                                  </div>
                                  <div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:center;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-alternates:normal;font-variant-east-asian:normal;margin:0px;line-height:normal">Visit <a href="http://kartoza.com/" target="_blank"><span>http://kartoza.com</span></a> to
                                    find out about open source:</div>
                                  <div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:center;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-alternates:normal;font-variant-east-asian:normal;margin:0px;line-height:normal;min-height:14px"><br>
                                  </div>
                                  <div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:center;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-alternates:normal;font-variant-east-asian:normal;margin:0px;line-height:normal">Desktop GIS
                                    programming services</div>
                                  <div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:center;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-alternates:normal;font-variant-east-asian:normal;margin:0px;line-height:normal">Geospatial web
                                    development</div>
                                  <div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:center;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-alternates:normal;font-variant-east-asian:normal;margin:0px;line-height:normal">GIS Training</div>
                                  <div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:center;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-alternates:normal;font-variant-east-asian:normal;margin:0px;line-height:normal">Consulting Services</div>
                                  <div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:center;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-alternates:normal;font-variant-east-asian:normal;margin:0px;line-height:normal;min-height:14px"><br>
                                  </div>
                                  <div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:center;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-alternates:normal;font-variant-east-asian:normal;margin:0px;line-height:normal"><b>Skype</b>:
                                    timlinux </div>
                                  <div style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:center;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-alternates:normal;font-variant-east-asian:normal;margin:0px;line-height:normal"><b>IRC:</b><span class="m_6208825008050013630Apple-converted-space"> </span>timlinux
                                    on #qgis at <a href="http://freenode.net" target="_blank">freenode.net</a></div>
                                </span></span></span></span></span></span></span></span></span></div>
            </div>
            <br>
          </blockquote>
          <br>
          <br>
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          <br>
          <pre>______________________________<wbr>_________________
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        <br>
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        <br>
        <pre>______________________________<wbr>_________________
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      <br>
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      <br>
      <pre>______________________________<wbr>_________________
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