Hi, our metrics are reflecting a sudden growth of unreviewed changes in Gerrit. Your attention and interpretations are welcome.
http://korma.wmflabs.org/browser/gerrit_review_queue.html
Look at the green line in the first graph, "Volume of open changesets". It shows the number of open changesets waiting for a review (WIP and -1 are excluded). In the last months, the number of changesets waiting for review has gone from 311 (June) to 529 (July) and 790 (August).
The increase is so high that first I thought the problem was in the metric, but Alvaro has reviewed the raw data and says that the metric is legit.
https://bugzilla.wikimedia.org/show_bug.cgi?id=70278
Trying to find an explanation, I went to the MediaWiki Core repository, and there are some inusual curves there as well:
http://korma.wmflabs.org/browser/repository.html?repository=gerrit.wikimedia...
However, not even these numbers alone would explain the increase.
Has there been an unusual activity (or lack of reviews) in Gerrit or are we missing an important detail in the metrics?
(pause)
In any case, in the past weeks I have been chasing old open reviews and in general I get the impression that developers/maintainers are too busy to review so many contributions. The tricky part is that many (most?) of those contributions come from the same developers/maintainers...
Simplifying a lot the picture, it looks as if we can't review code because we are busy writing code that won't be reviewed because we are busy writing code that won't be reviewed because... I'm sure this representation is unfair, but you get the point.
In many cases, unreviewed patches rotting mean real resources put into waste -- right? Maybe teams should prioritize the attention to open changesets at the expense of writing new code themselves? It's a real question and I won't pretend to have an answer. Different teams and repositories probably have different answers.