<div dir="ltr">









    
    <a class="gmail-js-post-issue gmail-flex--item gmail-s-btn gmail-s-btn__unset gmail-c-pointer gmail-py6 gmail-mx-auto" href="https://gis.stackexchange.com/posts/494155/timeline" aria-label="Timeline" aria-describedby="--stacks-s-tooltip-e9ug85l2"></a><div class="gmail-votecell gmail-post-layout--left"><div class="gmail-js-voting-container gmail-d-flex gmail-jc-center gmail-fd-column gmail-ai-center gmail-gs4 gmail-fc-black-300">

</div>

        </div><div class="gmail-postcell gmail-post-layout--right">
    
    <div class="gmail-s-prose gmail-js-post-body">
                
<p>Dear all, </p><p>I want to compare a geoprocessing done in QGIS and PostGIS. It 
involves a union of two large polygonal vector layers.The processing in 
QGIS tooks 1.5 hours on a well-equipped workstation (32 GB of RAM). I 
was never able to complete the processing on PostGIS.</p>
<p>Here is the tested  SQL query:</p>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><code class="gmail-hljs gmail-language-sql"><span class="gmail-hljs-keyword">create</span> <span class="gmail-hljs-keyword">table</span> public.union <span class="gmail-hljs-keyword">as</span>
<span class="gmail-hljs-keyword">select</span> st_union(ST_Forece2D(mos.geom), ST_Forece2D(bd_topo_bat.geom))
<span class="gmail-hljs-keyword">from</span> public.mos, public.bd_topo_bat
</code></blockquote>
<p>Here is the error message:</p>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><code class="gmail-hljs gmail-language-sql">ERROR: could <span class="gmail-hljs-keyword">not</span> extend file "base/19370/76968.57" <span class="gmail-hljs-keyword">with</span> FileFallocate(): <span class="gmail-hljs-keyword">No</span> space <span class="gmail-hljs-keyword">left</span> <span class="gmail-hljs-keyword">on</span> device HINT: <span class="gmail-hljs-keyword">Check</span> available disk space. ERROR: Could <span class="gmail-hljs-keyword">not</span> extend file "base/19370/76968.57" <span class="gmail-hljs-keyword">with</span> FileFallocate(): <span class="gmail-hljs-keyword">No</span> space <span class="gmail-hljs-keyword">left</span> <span class="gmail-hljs-keyword">on</span> device <span class="gmail-hljs-keyword">SQL</span> state: <span class="gmail-hljs-number">53100</span>
</code></blockquote>
<p>The error message is related to a problem with the temporary log 
file. In the postgresql.conf file, I edited the file by setting the 
value of log_temp_files = 10240. The default value was -1. I took this 
action based on this post: <a href="https://stackoverflow.com/questions/50833992/postgresql-no-space-left-on-device">https://stackoverflow.com/questions/50833992/postgresql-no-space-left-on-device</a></p>
    </div></div>Thanks so much. </div>