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<DIV dir=ltr align=left><FONT size=2 face=微软雅黑><A
href="http://www.postgis.org/documentation/manual-svn/ST_DWithin.html">http://www.postgis.org/documentation/manual-svn/ST_DWithin.html</A></FONT></DIV><FONT
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<FONT size=2 face=Tahoma><B>From:</B>
postgis-users-bounces@postgis.refractions.net
[mailto:postgis-users-bounces@postgis.refractions.net] <B>On Behalf Of
</B>superman0920<BR><B>Sent:</B> Friday, May 04, 2012 10:11 PM<BR><B>To:</B>
postgis-users<BR><B>Subject:</B> [postgis-users] about range
query<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV>hi</DIV>
<DIV>I have over 8500000 records in the postgresql and every record has a
geom column what is store a point.</DIV>
<DIV>I get a point <SPAN class=keyword>coordinate(eg 116.1124,39.9046
)</SPAN><SPAN class=phonetic> and I want to know the <SPAN
class=keyword>coordinates</SPAN><SPAN class=phonetic> of db points which is
in 500m range.</SPAN></SPAN></DIV>
<DIV><SPAN class=phonetic><SPAN class=phonetic></SPAN></SPAN> </DIV>
<DIV><SPAN class=phonetic><SPAN class=phonetic>I use </DIV>
<DIV style="COLOR: #3366ff">ST_Distance(</DIV>
<DIV style="COLOR: #3366ff">the_geom,</DIV>
<DIV style="COLOR: #3366ff">'srid=4326;point(116.1124 39.9046)'</DIV>
<DIV style="COLOR: #3366ff">) <= 500</DIV>
<DIV>but the query is very slow(about take 15s)</DIV>
<DIV> </DIV>
<DIV>Is there some another way can do fast ?</DIV></SPAN></SPAN><SPAN
class=phonetic></SPAN>
<DIV> </DIV>
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<DIV><SPAN>superman0920</SPAN></DIV></BLOCKQUOTE></BODY></HTML>