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<p class="MsoNormal">Hello,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="EN-US">I am having to import Raster (.tiff) into Postgres using the raster2pgsql tool. The raster used is 12MB in size and the Postgres version is 9.1 on Ubuntu 13.10.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">The virtual machine has the following hardware specs.<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1"><![if !supportLists]><span lang="EN-US"><span style="mso-list:Ignore">-<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-US">17408 Memory<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1"><![if !supportLists]><span lang="EN-US"><span style="mso-list:Ignore">-<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-US">4 Processors<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1"><![if !supportLists]><span lang="EN-US"><span style="mso-list:Ignore">-<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-US">16GB HDD<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">The command used to import (with the parameters) is: raster2pgsql -s 4326 -I -C -M -R -d -l 4 U:\Desktop\ilatlon_float.tif -F -t 8x8 ilatlon8x8|psql -d Raster
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">And the tile size varies from 8x8 all the way up till 2048 (power of 2s).<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">My results from the query ran showed that with larger tile size, the query has a faster returned timing.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">This trend is however opposite to some of the similar tests conducted by others (from the internet), where their conclusion was smaller tile size will have better performance.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">This is my one of the query I ran:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">EXPLAIN (ANALYZE,BUFFERS)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">SELECT DISTINCT ST_Intersection(r.rast::geometry,q.rast::geometry)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">FROM ilatlon32x32 as r, boundedilatlon32x32 as q;<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Is someone able to give advice on this, if this result that I obtained was legit? Or suggest where could the problem be that gave this result?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Zhi Feng<o:p></o:p></span></p>
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