I have discovered lately that I am need of something people are in the midst of inventing - geosyncronization. A preliminary look shows that a client that adds or updates our databases from WFS feeds is straightforward. However, for this to work well, both us and other players in the area also need to be providing a change feed which does not look so straightforward with existing technology. Does anyone know if there are geoserver developers/associates starting to look at this space?
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Hi,
Somebody did something with Geoserver and checksums last week if I remember right. That made me to think if it could be possible to calculate checksums for each feature by utilizing all the attributes and geometries and maintain a list of the feature-IDs and checksums both on the main db and clone db side. Then it might be possible to run a comparison at any time between the databases and create four lists: features to keep, update, delete or insert for making making the contents of the clone identical with the main db.
Synchonizing could perhaps be done with WFS by running first delete for all the features which should be deleted or updated and then by ordering the inserts and updates from the main db. Some special service could be able to do updates in place but with WFS I believe updates should be converted into deleles and inserts. Obviously features should have unique IDs but they can not be used as primary keys and real primary keys should be left out when calculating the checksums.
-Jukka Rahkonen-
________________________________________
Phil Scadden wrote:
I have discovered lately that I am need of something people are in the
midst of inventing - geosyncronization. A preliminary look shows that a
client that adds or updates our databases from WFS feeds is
straightforward. However, for this to work well, both us and other
players in the area also need to be providing a change feed which does
not look so straightforward with existing technology. Does anyone know
if there are geoserver developers/associates starting to look at this space?
Notice: This email and any attachments are confidential.
If received in error please destroy and immediately notify us.
Do not copy or disclose the contents.
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