[mapserver-users] performance question - joining dbf tables in MapServer
Lime, Steve D (MNIT)
Steve.Lime at state.mn.us
Fri Aug 19 11:53:05 PDT 2016
Joins are really meant for simple look ups so there is no indexing or anything like that with the DBF and flat file options. Also note that JOINs are post-query-only so you couldn't label based on a joined column, nor query on a joined attribute. You could keep information you wanted to display as the result of a query however.
In short, if you have a relatively small set of attributes that you want to display as a result of a query then a JOIN might work well. Does that help?
Steve
From: mapserver-users [mailto:mapserver-users-bounces at lists.osgeo.org] On Behalf Of Mark Volz
Sent: Thursday, August 18, 2016 8:23 AM
To: mapserver-users at lists.osgeo.org
Subject: [mapserver-users] performance question - joining dbf tables in MapServer
Hello,
I am considering joining my tax data to my parcel dataset on the fly using the MapServer Join function. This way I can update my tax data weekly, and my parcels as needed. My tax data will be in a dbf and my parcels will be in a shapefile.
Questions:
* Is there any performance hit using joining on the fly vs keeping the tax data in the shapefile?
* Are there any tips I should be aware about to make the joins work faster?
http://mapserver.org/mapfile/join.html.
Thank You!
Sincerely,
Mark Volz
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