Geomap is insanely slow after migration to Graphite in NAV 4.0

[Morten Brekkevold]

Due to the way Geomap handles fetching of load metrics (at the last minute), it became insanely inefficient after the transition from local RRD files to the service-based graphite-web.

Each metric is currently retrieved in a separate HTTP request to graphite-web, which translates to massive overhead.

The Geomap load fetching code should be refactored to discover, at an earlier stage, which load metrics are needed, and fetch these in bulk from graphite-web.

[Morten Brekkevold (mbrekkevold)]

fix here: https://nav.uninett.no/hg/stable/rev/3f7bdfc1905e

There are still some improvements that could be made, like picking data only from one of the link partners per link.