For my project, I have successfully created a PostgreSQL database of the entire planet file using osm2pgsql. My next task was to sucessfuly update the database using daily change files through the well renowned osmosis -> osm2pgsql (append) process chain.
To test updates, I added some hiking trails to the OpenStreetMap. The nodes were auto snapped to the edges of existing roads in the forest in the OSM editing session (website). I pulled the change file with osmosis using the sequence id, per standard, and used the osm2pgsql --append command, as outline by numerous help sites and forums. My new trail came through, and was visually proven using a Geoserver platform to serve the postgres data.
Here is the problem...any existing road that was modified was absent in the osm_line data after the update. The two roads to which either end of the newly digitized trail were gone. They are still in the map, as confirmed by a Geofabrik download of the local area, as well as by simply going to the OSM website. Additionally, an existing trail that was incorrect and I moved a few nodes within is also gone. It seems my command (either Osmosis or Osm2pgsql append) is wrong, and is only applying new features and knocking out anything that changed.
Hoping we have some OSM gurus that can help.
My two commands are as follows:
osmosis --read-replication-interval workingDirectory=D:\osm_updates --simplify-change --write-xml-change D:\osm_updates\changes.osc.gz osm2pgsql --append -d planet -U postgres -S default.style -E 4326 -C 8000 --slim --number-processes 6 d:\osm_updates\changes.osc.gz