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</o:shapelayout></xml><![endif]--></head><body lang=FR-CA link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span lang=EN-US style='font-size:7.5pt;font-family:"Verdana","sans-serif";color:black;background:white'>Hello,<span class=apple-converted-space> </span></span><span lang=EN-US style='font-size:7.5pt;font-family:"Verdana","sans-serif";color:black'><br><br><span style='background:white'> I don't want to denigrate PostGIS in any way and I know that my comparison may be wrong but I'm trying to understand why a basic ST_Intersection of two relatively small layers (< 1000 polygons) take about 1m40 sec in PostGIS(2.0 on PG 9.2 on Windows) while applying the ArcGIS Intersect on same layers and machine take about 2 sec?<span class=apple-converted-space> </span></span><br><br><span style='background:white'>I'm aware of some PostgreSQL tuning settings but even applying basic tuning recommendation for PostGIS I'm facing the same problem...<span class=apple-converted-space> </span></span><br style='orphans: 2;text-align:start;widows: 2;-webkit-text-size-adjust: auto;-webkit-text-stroke-width: 0px;word-spacing:0px'><br><o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:7.5pt;font-family:"Verdana","sans-serif";color:black'>My two layers also have a spatial index.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:7.5pt;font-family:"Verdana","sans-serif";color:black'><br><span style='background:white'>Is it normal behavior? Any suggestion for reaching better performance?<span class=apple-converted-space> </span></span><br><br><span style='background:white'>Note that I'm also using ST_Intersects on the join to filter only intersecting features...<span class=apple-converted-space> </span></span><br><br></span><span style='font-size:7.5pt;font-family:"Verdana","sans-serif";color:black;background:white'>Thanks a lot<span class=apple-converted-space> </span></span><span style='font-size:7.5pt;font-family:"Verdana","sans-serif";color:black'><br><br><span style='background:white'>Etienne</span></span><o:p></o:p></p></div></body></html>