Hi folks,
One item that comes up pretty frequently in our regular conversations with the Wikidata folks is the question of how change propagation should work. This email is largely directed at the relevant folks in WMF's Ops and Platform Eng groups (and obviously, also the Wikidata team), but I'm erring on the side of distributing too widely rather than too narrowly. I originally asked Daniel to send this (earlier today my time, which was late in his day), but decided that even though I'm not going to be as good at describing the technical details (and I'm hoping he chimes in), I know a lot better what I was asking for, so I should just write it.
The spec is here: https://meta.wikimedia.org/wiki/Wikidata/Notes/Change_propagation#Dispatchin...
The thing that isn't covered here is how it works today, which I'll try to quickly sum up. Basically, it's a single cron job, running on hume[1]. So, that means that when a change is made on wikidata.org, one has to wait for this job to get around to running before the item. It'd be good for someone from the Wikidata team to
We've declared that Good Enough(tm) for now, where "now" is the period of time where we'll be running the Wikidata client on a small number of wikis (currently test2, soon Hungarian Wikipedia).
The problem is that we don't have a good plan for a permanent solution nailed down. It feels like we should make this work with the job queue, but the worry is that once Wikidata clients are on every single wiki, we're going to basically generate hundreds of jobs (one per wiki) for every change made on the central wikidata.org wiki.
Guidance on what a permanent solution should look like? If you'd like to wait for Daniel to clarify some of the tech details before answering, that's fine.
Rob