Still an issue.

Now starts with Open Date = Nov 20th, 2014 so it really only covers the last two years.

(PEBKAC: By default the view is only about Last 2 years, Andre...)

"Backlog" on https://wikimedia.biterg.io/app/kibana#/dashboard/Gerrit-Backlog orders by Submission Date of the initial Patch Set.
(In contrast, "Oldest open Gerrit changesets without code review" on http://korma.wmflabs.org/browser/scr-backlog.html orders by Last Update / Patch Set, not by Submission Date of the initial Patch Set.)

Going to Last 5 years on https://wikimedia.biterg.io/app/kibana#/dashboard/Gerrit-Backlog , the oldest listed patchset is https://gerrit.wikimedia.org/r/#/c/100141/ from Dec 2013, and indeed https://gerrit.wikimedia.org/r/#/c/49474/ (Submission Date of the initiual Patch Set: Feb 2013) seems to be missing so data seems to be incomplete.

I'll adjust the task summary here accordingly.

@Aklapper , @Lcanasdiaz we were indeed missing changesets. The point is that tables in Kibana are ordered by a given metric and in this case this was the column "changeset". However this has to be ordered by the open date or the days open.

So the problem was that as we had that column, the list of changesets was randomly selected. But at the very beginning we chose to have the whole list of changesets and not only 100 of them. Then we faced strong performance issues and we decided to have only 100 of those changesets. And having 100 of them and the column changeset to 1, we forced Kibana to randomly select 100 of them (and this is basically the issue here).

How to fix this: I removed the changeset column and added two new metrics (in the nomenclature of Kibana): max(open_date) and max(open_days). As we only have one open date and one open days per changeset, then we forced Kibana to order by the open date (our new metric) and now this properly works :).