[OSM-dev] Fixing the history tab

[Paweł Paprota]

Sorry, I did not finish one of the sentences properly - about knn in
Postgres:

* PostgreSQL now supports k nearest neighbors indexing[1][2] - the
distance function/operator could be defined for OSM changesets so that a
query for given tile (or tile range) uses the knn index and at the same
time returns only k nearest neighbors (where "nearest" would be
"latest").

Also - to add to my previous comments about the solution - I am 100%
sure that there are people who know how to solve this kind of problem,
even using the tools we have (Postgres) - so part of the task is
reaching out to them and consulting about the solution.