[Mapserver-users] Performance of indexed shape files (W2K/php_mapscript)
Ed McNierney
ed at topozone.com
Mon Mar 8 10:39:35 EST 2004
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Uwe -
=20
Performance can be a complicated issue; if, for example, there are other
factors slowing down your performance, the improvements due to indexing
may be so small as to be almost invisible.
=20
I'd recommend a stripped-down test using the MapServer CGI - what else
is your PHP code doing? Are you using template files (i.e. =
mode=3Dbrowse)
or a direct map request (mode=3Dmap)? You should be using the latter
(mode=3Dmap) for your performance testing, because otherwise you're =
adding
the overhead of writing a temporary file to disk, which may be a serious
delay.
=20
- Ed
=20
Ed McNierney
President and Chief Mapmaker
TopoZone.com / Maps a la carte, Inc.
73 Princeton Street, Suite 305
North Chelmsford, MA 01863
ed at topozone.com
(978) 251-4242=20
_____ =20
From: ujunge at pmcentral.com [mailto:ujunge at pmcentral.com]=20
Sent: Sunday, March 07, 2004 11:36 PM
To: mapserver-users at lists.gis.umn.edu
Subject: [Mapserver-users] Performance of indexed shape files
(W2K/php_mapscript)
Hello MapServer Users,
=20
I do not see any performance differences using shapefile indexes,
generated by precompiled shptree.exe (8/6/2003).
In fact, no matter which command line parameters have been choosen,=20
shapefiles will not render faster nor slower if the qix-file is
present or not.=20
=20
It doesn't even make a difference what shape-file I'am looking at.
=20
For example, taking a 50MB shape file (200K lines) with street data
covering CA or TX and zooming in=20
about 1 mile in any city takes exactly the same rendering time, with or
without qix-files.
=20
As another example, a 80MB filled polygon layer (16K polygons),
displaying urban-areas and covering the entire US,=20
takes the same time to render (zooing in about 30miles), again with or
without index-files.
=20
With respect to the performance difference,
- it doesn't matter, if the map for a specific area is requested the
first time=20
or requested subsequently with small area-hanges .
- it dosen't matter, if only one layer is requested, or more layers,
which may not be indexed.
=20
All layers have the same projection (WGS84) , the is no reprojection on
the fly.
=20
Does it mean, that the qix-index is not used at all ?
=20
Is this a Windows - Distribution issue ? (i would like to use Linux, but
the customer not)
=20
I use the precomiled php_mapscript_40.dll (8/5/2003) on a PIII
W2K-Server (512MB) .
=20
=20
=20
Greetings,
=20
=20
Uwe Junge
=20
=20
=20
Uwe Junge
PMCentral Systems, Inc.
4201 Pinefield Court
Fairfax, Virginia 22033
=20
(703) 378-0952
=20
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<DIV dir=3Dltr align=3Dleft><SPAN class=3D138113715-08032004><FONT =
face=3DArial=20
color=3D#0000ff size=3D2>Uwe -</FONT></SPAN></DIV>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D138113715-08032004><FONT =
face=3DArial=20
color=3D#0000ff size=3D2></FONT></SPAN> </DIV>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D138113715-08032004><FONT =
face=3DArial=20
color=3D#0000ff size=3D2>Performance can be a complicated issue; if, for =
example,=20
there are other factors slowing down your performance, the improvements =
due to=20
indexing may be so small as to be almost invisible.</FONT></SPAN></DIV>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D138113715-08032004><FONT =
face=3DArial=20
color=3D#0000ff size=3D2></FONT></SPAN> </DIV>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D138113715-08032004><FONT =
face=3DArial=20
color=3D#0000ff size=3D2>I'd recommend a stripped-down test using the =
MapServer CGI=20
- what else is your PHP code doing? Are you using template files =
(i.e.=20
mode=3Dbrowse) or a direct map request (mode=3Dmap)? You should be =
using the=20
latter (mode=3Dmap) for your performance testing, because otherwise =
you're adding=20
the overhead of writing a temporary file to disk, which may be a serious =
delay.</FONT></SPAN></DIV>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D138113715-08032004><FONT =
face=3DArial=20
color=3D#0000ff size=3D2></FONT></SPAN> </DIV>
<DIV dir=3Dltr align=3Dleft><SPAN =
class=3D138113715-08032004> <FONT=20
face=3DArial color=3D#0000ff size=3D2>- Ed</FONT></SPAN></DIV>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D138113715-08032004><FONT =
face=3DArial=20
color=3D#0000ff size=3D2></FONT></SPAN> </DIV>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D138113715-08032004>
<P><FONT size=3D2>Ed McNierney<BR>President and Chief =
Mapmaker<BR>TopoZone.com /=20
Maps a la carte, Inc.<BR>73 Princeton Street, Suite 305<BR>North =
Chelmsford,=20
MA 01863<BR>ed at topozone.com<BR>(978) 251-4242 =
</FONT></P></SPAN></DIV><BR>
<DIV class=3DOutlookMessageHeader lang=3Den-us dir=3Dltr align=3Dleft>
<HR tabIndex=3D-1>
<FONT face=3DTahoma size=3D2><B>From:</B> ujunge at pmcentral.com=20
[mailto:ujunge at pmcentral.com] <BR><B>Sent:</B> Sunday, March 07, 2004 =
11:36=20
PM<BR><B>To:</B> mapserver-users at lists.gis.umn.edu<BR><B>Subject:</B>=20
[Mapserver-users] Performance of indexed shape files=20
(W2K/php_mapscript)<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV><FONT face=3DArial size=3D2>
<DIV><FONT face=3DArial size=3D2>Hello MapServer Users,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I do not see any performance =
differences using=20
shapefile indexes, generated by precompiled shptree.exe =
(8/6/2003).</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>In fact, no matter which command=20
line parameters have been choosen, </FONT></DIV>
<DIV><FONT face=3DArial size=3D2>shapefiles will not render faster nor =
slower =20
if </FONT><FONT face=3DArial size=3D2>the qix-file is present or =
not.=20
</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>It doesn't even make a difference what=20
shape-file I'am looking at.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>For example, taking a 50MB shape =
file (200K=20
lines) with street data </FONT><FONT face=3DArial size=3D2>covering CA =
or TX and=20
zooming in </FONT></DIV>
<DIV><FONT face=3DArial size=3D2>about 1 mile in any city takes exactly =
the same=20
rendering time, with or without qix-files.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>As another example, a 80MB filled =
polygon layer=20
(16K polygons), displaying urban-areas and covering the entire US, =
</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>takes the same time to render (zooing =
in about=20
30miles), again with or without index-files.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>With respect to the performance=20
difference,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>- it doesn't matter, if =
the map for a=20
specific area is requested the first time </FONT></DIV>
<DIV><FONT face=3DArial size=3D2> or requested=20
subsequently with small area-hanges .</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>- it dosen't matter, if only one layer =
is=20
requested, or more layers, which may not be indexed.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>All layers have the same projection =
(WGS84) , the=20
is no reprojection on the fly.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Does it mean, that the qix-index is not =
used at all=20
?</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Is this a Windows - Distribution issue =
?=20
(</FONT><FONT face=3DArial size=3D2>i would like to use Linux, but the =
customer=20
not)</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I use the =
precomiled php_mapscript_40.dll=20
(8/5/2003) on a PIII W2K-Server (512MB) .</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Greetings,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Uwe Junge</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Uwe Junge<BR>PMCentral Systems, =
Inc.<BR>4201=20
Pinefield Court<BR>Fairfax, Virginia 22033</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>(703) 378-0952</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2><BR>---<BR>Outgoing mail is certified =
Virus=20
Free.<BR>Checked by AVG anti-virus system (<A=20
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