[Tile-serving] [openstreetmap/osm2pgsql] Add docs about using `create_only` columns for postprocessed data (#1233)

[Jochen Topf]

a) `GENERATED` columns are only supported since PostgreSQL 12.
b) There is currently no way to create `GENERATED` columns with the flex backend. I thought about adding it, but I am unsure about how to best do this given a). And adding more and more column options might be a rabbit hole I don't want to go down at the moment.

So basically this documents a usable work-around for something that we might support in the future with `GENERATED`, but for the time being this should work well enough and once people do these kinds of things, we'll have a better idea whether and how we want to add proper support in osm2pgsql for this kind of thing.

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/openstreetmap/osm2pgsql/pull/1233#issuecomment-650023370
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/tile-serving/attachments/20200626/18e89f3c/attachment-0001.htm>