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<DIV dir=ltr align=left><SPAN class=937501519-19072009><FONT color=#0000ff
size=2 face=Arial>Nicklas,</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=937501519-19072009><FONT color=#0000ff
size=2 face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=937501519-19072009><FONT color=#0000ff
size=2 face=Arial> I can't quite see how max distance would help
ST_DWithin. It seems it would help the Fully_DWithin, but don't see how it
helps the ST_DWithin. </FONT></SPAN><SPAN class=937501519-19072009><FONT
color=#0000ff size=2 face=Arial>Granted I haven't given it much thought.
</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=937501519-19072009><FONT color=#0000ff
size=2 face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=937501519-19072009><FONT color=#0000ff
size=2 face=Arial>Thanks,</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=937501519-19072009><FONT color=#0000ff
size=2 face=Arial>Regina</FONT></SPAN></DIV><BR>
<DIV dir=ltr lang=en-us class=OutlookMessageHeader align=left>
<HR tabIndex=-1>
<FONT size=2 face=Tahoma><B>From:</B>
postgis-devel-bounces@postgis.refractions.net
[mailto:postgis-devel-bounces@postgis.refractions.net] <B>On Behalf Of
</B>nicklas.aven@jordogskog.no<BR><B>Sent:</B> Sunday, July 19, 2009 2:39
PM<BR><B>To:</B> PostGIS Development Discussion<BR><B>Subject:</B> Re:
[postgis-devel] Caching function calls with CTEs<BR></FONT><BR></DIV>
<DIV></DIV>Yes,that one I can see.<BR><BR>About the nearest neighbour I have
thought about using st_max_distance against the bounding boxes to find the one
with smallest max_distance. That value ought to be good to use in the st_dwithin
part of the query. <BR><BR>Maybe it would even be worth the effort to use
st_distance from the geometry found with the "max_distance" boundingbox to usi
in in st_dwithin. <BR><BR>Hope it is possible to understand what I mean. It is
at least one release ahead but possible to test
:-)<BR><BR><BR>/Nicklas<BR><BR><SPAN class=content><PRE><SPAN class=syntax0><BR>
</SPAN></PRE></SPAN><BR>2009-07-19 Paragon Corporation wrote:<BR><BR>>
<DIV align=left><SPAN
style="FONT-FAMILY: Arial; COLOR: rgb(0,0,255); FONT-SIZE: 10pt">Windowing
functions come in especially handy for nearest neighbor search getting top n per
location. We are going to demonstrate that in our OSCON conference.
Slides and materials will of course will be available after the conference is
over.</SPAN></DIV><BR>>>
<DIV align=left>
<HR>
<SPAN style="FONT-FAMILY: Tahoma; FONT-SIZE: 10pt"><SPAN
style="FONT-WEIGHT: bold">From:</SPAN>
postgis-devel-bounces@postgis.refractions.net
[mailto:postgis-devel-bounces@postgis.refractions.net] <SPAN
style="FONT-WEIGHT: bold">On Behalf Of
</SPAN>nicklas.aven@jordogskog.no<BR>><SPAN
style="FONT-WEIGHT: bold">Sent:</SPAN> Sunday, July 19, 2009 1:52
PM<BR>><SPAN style="FONT-WEIGHT: bold">To:</SPAN> PostGIS Development
Discussion<BR>><SPAN style="FONT-WEIGHT: bold">Subject:</SPAN> Re:
[postgis-devel] Caching function calls with
CTEs<BR>></SPAN><BR>></DIV>>
<DIV> </DIV>This is really cool Regina and Leo<BR>><BR>>It's a new
way of thinking for me to to use this recursive thing, but I can see that it is
very useful.<BR>>I hope I will get some time in the near future to try to
understand it better.<BR>><BR>>Also the windowing functions together with
postgis aggregate function will be fun to
try.<BR>><BR>>/Nicklas<BR>><BR>><BR>><BR>><BR>><BR>>2009-07-17
Paragon Corporation wrote:<BR>><BR>>Nicklas,<BR>>><BR>>>We
tried CTEs against that annoying issue of functions not being cached
in<BR>>>the same row. Preliminary tests seem to suggest it might be the
ideal<BR>>>solution for this.<BR>>>We suspect it will also be good
in many other scenarios where the planner<BR>>>refuses to use indexes in
the right order
etc.<BR>>><BR>>>http://www.postgresonline.com/journal/index.php?/archives/127-guid.html<BR>>><BR>>>We
are going to test with real spatial queries next in preparation for
our<BR>>>OSCON presentation next
week.<BR>>><BR>>>http://en.oreilly.com/oscon2009/public/schedule/detail/7859<BR>>>Sadly
it looks like we probably won't have 1.4 out in time for
our<BR>>>presentation - oh well
:(<BR>>><BR>>><BR>>>Anyrate take a look and test with your
data to see if it speeds up your<BR>>>queries.<BR>>><BR>>>L
&
R<BR>>><BR>>><BR>>>_______________________________________________<BR>>>postgis-devel
mailing
list<BR>>>postgis-devel@postgis.refractions.net<BR>>>http://postgis.refractions.net/mailman/listinfo/postgis-devel<BR>>><BR>>>
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