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</o:shapelayout></xml><![endif]--></head><body lang=FR link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>Hi,<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Verdana","sans-serif"'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>I have a pgsql postgis function that last about an hour on an Hp Envy (W10, i7-6500 CPU 2,5 Ghz 8go). This function is calculating minimum distance between each nodes of table x (12000 nodes) and table y (42000 nodes)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Verdana","sans-serif"'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>FOR row IN <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Verdana","sans-serif"'> SELECT code,ST_AsEwkt(ST_StartPoint(geom)) as geom1 FROM t_x<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>LOOP<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Verdana","sans-serif"'> FOR row1 IN<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Verdana","sans-serif"'> SELECT code, ST_Distance(ST_AsEwkt(geom)::text,row.geom1) FROM t_y order by ST_Distance(ST_AsEwkt(geom)::text,row.geom1) LIMIT 1<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Verdana","sans-serif"'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Verdana","sans-serif"'> </span><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>LOOP<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'> END LOOP;<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>....<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>What I don't understand is that postgresql server process CPU is stable during all that time at 30/31% with no other process running. Details of each processor 1 to 3 shows that all 4 uses 30%. Disk and network usage are 0% (database is local) Ram usage is 47% and Postgresql server uses process only 7,4 Mo.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Verdana","sans-serif"'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>My question is "Why postgres process uses such a precise and constant cpu and doesn't grow up to more than 30% ?" I didn't find any parameter forcing such a limit in order to reduce duration of this calculation.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Verdana","sans-serif"'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>Thanks for any answer,<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Verdana","sans-serif"'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>Olivier<o:p></o:p></span></p></div>
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