On Thu, Jan 18, 2018 at 8:16 AM, Nuria Ruiz <nuria@wikimedia.org> wrote:

>while EventLogging data gets stored in a different, unrelated way
Not really, This has changed quite a bit as of the last two quarters. Eventlogging data as of recent gets preprocessed and refined similar to how webrequest data is preprocessed and refined. You can have a dashboard on top of some eventlogging schemas on superset in the same way you have a dashboard that displays pageview data on superset. 
I don't see how this addresses Gergo's larger point about the difference between consistently tallying content consumption (pageviews, previews, mediaviewer image views) and analyzing UI interactions (which is the main use case that EventLogging has been developed and used for). There are really quite a few differences between these two. For example, UI instrumentations on the web are almost always sampled, because that yields enough data to answer UI questions - but on the other hand tend to record much more detail about the individual interaction. In contrast, we register all pageviews unsampled, but don't keep a permanent record of every single one of them with precise timestamps - rather, we have aggregated tables (pageview_hourly in particular). Our EventLogging backend is not tailored to that. 


See dashboards on superset (user required).

And (again, user required) EL data on druid, this very same data we are talking about, page previews:

That's actually not the "very same data we are talking about". You can rest assured that the web team (and Sam in particular) has already been aware of the existence of the Popups instrumentation for page previews. The team spent considerable effort building it in order to understand how users interact with the feature's UI. Now comes the separate effort of systematically tallying content consumption from this new channel. Superset and Pivot are great, but are nowhere near providing all the ways that WMF analysts and community members currently have to study pageview data. Storing data about seen previews in the same way as we do for pageviews, for example in the pageview_hourly (suitably tagged, perhaps giving that table a more general name) would facilitate that a lot, by allowing us to largely reuse the work that during the past few years went into getting pageview aggregation right. 

>I was going to make the point that #2 already has a processing pipeline established whereas #1 doesn't.
This is incorrect, we mark as "preview" data that we want to exclude from processing, see: 
Naming is unfortunate but previews are really "preloads" as in requests we make (and cache locally) and maybe shown to users or not. 

But again, tracking of events is better done on an event based system and EL is such a system. 

Again, tracking of individual events is not the ultimate goal here.

Tilman Bayer
Senior Analyst
Wikimedia Foundation
IRC (Freenode): HaeB