<div dir="auto"><div><br><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, 20 June 2022, 11:42 pm David Marteau, <<a href="mailto:dmarteau@3liz.com">dmarteau@3liz.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div>
<p>Hi,</p>
<div dir="auto">> You should set the other new read optimisation
flags here -- see <a href="https://github.com/qgis/QGIS/blob/88ebb3f2f513dbce5a775f50e51ea0117f859c65/src/core/qgis.h#L1962" target="_blank" rel="noreferrer">https://github.com/qgis/QGIS/blob/88ebb3f2f513dbce5a775f50e51ea0117f859c65/src/core/qgis.h#L1962</a></div>
<div dir="auto"><br>
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<div dir="auto">These are already available also in 3.24 and we use
the `TrustLayerMetadata` in the above test. For server, the
other flags are not applicable (Getprint requests need print
layouts ).</div>
<div dir="auto"><br>
</div>
<div dir="auto">So that mean we are comparing 3.24 to 3.26 with same
level of read optimisation and that does not change the fact that,
for that very same level of read optimisation, project's loading
is incredibly slower in 3.26.<br></div></div></blockquote></div></div><div dir="auto"><br></div><div dir="auto">You'll need to set the new flags relating to skipping the 3d views and project style loading in order to compare properly. Neither of those things were occurring in 3.24, and both have an associated cost. And neither are relevant for server.</div><div dir="auto"><br></div><div dir="auto">Nyall</div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div dir="auto">
</div>
<div dir="auto"><br>
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<div dir="auto"><br>
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Le 20/06/2022 à 15:10, Nyall Dawson a écrit :<br>
<blockquote type="cite">
<div dir="auto">
<div><br>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Mon, 20 June 2022, 9:37
pm David Marteau via QGIS-Developer, <<a href="mailto:qgis-developer@lists.osgeo.org" target="_blank" rel="noreferrer">qgis-developer@lists.osgeo.org</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote">
<div>
<p>Hi,</p>
<p>I have noticed a huge drop of performance while
testing Qgis server with Qgis 3.26, from 10x to 30x
slower as usual.</p>
<p>Trying to reduce the problem I have found a huge
increase of time spend reading the project in 3.26
compared to 3.24.</p>
<p>Here some benchmark with very simple project from the
test data set. Note: the project has been updated with
qgis 3.26:</p>
<p>Qgis 3.24:<br>
======<br>
</p>
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<pre role="presentation"><span role="presentation"><span>readflags</span> <span>=</span> <span>QgsProject</span>.<span>ReadFlags</span>()<span>
readflags</span> <span>|=</span> <span>QgsProject</span>.<span>FlagTrustLayerMetadata</span></span></pre>
<pre role="presentation"><span role="presentation"><span></span><span>prj</span> <span>=</span> <span>QgsProject</span>()</span></pre>
<pre role="presentation"><span role="presentation"><span>%</span><span>timeit</span> <span>-</span><span>n</span> <span>1</span> <span>prj</span>.<span>read</span>(<span>f"</span>{<span>datapath</span>}<span>/france_parts.qgs"</span>,<span>readflags</span>)</span></pre>
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<div dir="auto">
<pre>> 15.7 ms ± 205 µs per loop (mean ± std. dev. of 7 runs, 1 loop each)
</pre>
</div>
<p>Qgis 3.26:<br>
======</p>
<div role="presentation">
<pre role="presentation"><span role="presentation"><span>readflags</span> <span>=</span> <span>QgsProject</span>.<span>ReadFlags</span>()
<span>readflags</span> <span>|=</span> <span>QgsProject</span>.<span>FlagTrustLayerMetadata</span></span></pre>
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</blockquote>
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</div>
<div dir="auto"><br>
</div>
<div dir="auto">You should set the other new read optimisation
flags here -- see <a href="https://github.com/qgis/QGIS/blob/88ebb3f2f513dbce5a775f50e51ea0117f859c65/src/core/qgis.h#L1962" target="_blank" rel="noreferrer">https://github.com/qgis/QGIS/blob/88ebb3f2f513dbce5a775f50e51ea0117f859c65/src/core/qgis.h#L1962</a></div>
<div dir="auto"><br>
</div>
<div dir="auto">Nyall</div>
<div dir="auto"><br>
</div>
<div dir="auto">
<div class="gmail_quote">
<blockquote class="gmail_quote">
<div>
<div role="presentation">
<pre role="presentation"><span role="presentation"><span></span><span>prj</span> <span>=</span> <span>QgsProject</span>()</span></pre>
<pre role="presentation"><span role="presentation"><span>%</span><span>timeit</span> <span>-</span><span>n</span> <span>1</span> <span>prj</span>.<span>read</span>(<span>f"</span>{<span>datapath</span>}<span>/france_parts.qgs"</span>,<span>readflags</span>)</span></pre>
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<div dir="auto">
<pre>195 ms ± 44 ms per loop (mean ± std. dev. of 7 runs, 1 loop each)
</pre>
<p>There is a factor x10 between Qgis 3.24 et Qgis
3.26 for the exact same project. <br>
This has serious impact on requests: landing page
catalog request time increased from approximatevely
110ms to more than 3.0s with our test data set.</p>
<br>
</div>
<div>
<p> <span>David Marteau</span> <br>
<a href="http://www.3liz.com" rel="noreferrer noreferrer" target="_blank">www.3liz.com</a>
<br>
<span> </span> </p>
</div>
</div>
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