Dear group,<div><br></div><div>I've been having trouble trying to do a nested PostGIS query on our system. The query looks something like this:</div><div><div><br></div><div><div><font face="'courier new', monospace"> SELECT count, geometry, ST_GeometryType(geometry)</font></div>
<div><font face="'courier new', monospace"> FROM (</font></div><div><font face="'courier new', monospace"> SELECT COUNT(*) AS count,</font></div><div><font face="'courier new', monospace"> ST_Buffer(ST_Buffer(ST_Union(ST_Buffer(ST_SimplifyPreserveTopology(geometry, 0.001), 1e-005)),.001), -.001) AS geometry</font></div>
<div><font face="'courier new', monospace"> FROM <table></font></div><div><font face="'courier new', monospace"> WHERE <criteria></font></div><div><font face="'courier new', monospace"> ORDER BY ST_GeoHash(geometry, 8), <other_fields></font></div>
<div><font face="'courier new', monospace"> LIMIT <limit> OFFSET <offset></font></div><div><font face="'courier new', monospace"> )</font></div><div><font face="'courier new', monospace"> ) AS i</font></div>
<div><font face="'courier new', monospace"> ;</font></div><div><font face="'courier new', monospace"><br></font></div><div><font face="arial, helvetica, sans-serif">This query has worked well for us numerous times, but is not working with this particular set of geometries. We have our <limit> set to 500000. The types of errors we receive look like one of these:</font></div>
<div><font face="arial, helvetica, sans-serif"><br></font></div></div><blockquote style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:40px;border-top-style:none;border-right-style:none;border-bottom-style:none;border-left-style:none;border-width:initial;border-color:initial;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px">
<div><div><font face="'courier new', monospace">server closed the connection unexpectedly</font></div></div><div><div><font face="'courier new', monospace">The connection to the server was lost. Attempting reset: Failed.</font></div>
</div></blockquote><div style="font-family:'courier new',monospace"><font face="'courier new', monospace"><br></font></div><font face="arial, helvetica, sans-serif">I have been able to run this query successfully by paring down my limit to 10000. As I mentioned above, it has worked well for us with sizes as large as 500000. </font><span style="font-family:arial,helvetica,sans-serif">We are running PostGIS 1.5.3 on Postgers 9.0.4 on 64-bit Linux.</span></div>
<div><div><font face="arial, helvetica, sans-serif"><br></font></div><div><font face="arial, helvetica, sans-serif">Any ideas what might be happening here?</font></div></div><p><font face="Verdana, sans-serif"><span style="font-size:10px"></span></font></p>
<font face="Verdana, sans-serif"><p style="font-size:small"><a name="SafeHtmlFilter_SafeHtmlFilter_SafeHtmlFilter_SafeHtmlFilter_SafeHtmlFilter_SafeHtmlFilter__MailAutoSig"><b><span style="font-size:10.0pt;color:black"><font face="verdana, sans-serif">Yusuf
Siddiqui </font></span></b></a></p>
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