[OSM-dev] Incoming osm2pgsql change without migrations

[Paul Norman]

There is an incoming change to osm2pgsql which changes the format of 
slim tables. This will change the schema of the slim tables, but have no 
impact on the rendering tables.

The change is to use unprojected coordinates in slim tables, and an 
osmium dense file array instead of flat nodes. There is no migration for 
old databases.

It only impacts you if you

- Run an osm2pgsql database that updates with diffs; or
- Develop software which relies on the internals of the slim nodes table 
or the flat nodes file (don't do this)

Nothing will change if you

- Only ever load data with --slim --drop or without --slim;
- Only ever update by reloading the database; or
- Only write software/styles which access the normal rendering tables

The pull request with details is 
https://github.com/openstreetmap/osm2pgsql/pull/668