Hi all,
I've tracked down an unexplained EL phenomenon that surfaced in our stats
as a false trend in our global stats.
The data I'm looking at specifically is coming from Media Viewer's
MultimediaViewerNetworkPerformance_* tables.
Have a look at this graph:
https://docs.google.com/spreadsheets/d/1PJsyzAyj74dctGCl4-09L7LS4AMZRh57G56…
the big change is on Jan 7th/8th
It shows how many EL events we've recorded, per client-reported country,
over the last 90 days. The sampling factor we use has been constant for
each wiki over that period. Thus, the distribution shouldn't evolve
drastically, aside from seasonal/local trends. Besides the Ukraine spike on
a particular date (probably related to world events), the graph before Jan
7th looks like what you would expect. Then, following the outage that
happened on Jan 7th, not only the balance is completely changed, but it
evolves over time (the US and China are keeping "higher than normal"
levels, while the rest seems to slide down lower than pre-7th quantities),
showing me that something strange is happening and is probably unresolved.
This balance shifting over time is really problematic for tracking Media
Viewer client-side network performance, because Chinese traffic suddenly
accounting for a bigger or smaller share of the overall recorded events
creates big swings in the global averages/percentiles (since network
performance in China is bad).