== Blockers
[x] All current EventLogging bugs are resolved and data is confirmed by @Tbayer (see T162672#3496940)
- Tracking task for @Tbayer's analysis: {T158172}
[x] Deployment must happen after green light from @ovasileva (see T162672#3496940)
== Plan (YMMV):
[x] Reset the instrumentation sampling rate to 0.001 for all wikis, i.e. revert {d5c4bd72}.
[] Deployment must happen in few stages (3 or more) in order to make rollback easier โ if we start overloading the edge caches (and origin servers potentially), say.
* Deploy to a chunk of 50 wikis and assess the impact on Page Previews, RESTBase, and Varnish performance, if any.
* https://grafana.wikimedia.org/dashboard/db/reading-web-page-previews
* https://grafana.wikimedia.org/dashboard/db/varnish-caching?var-cluster=text&var-site=All
* If there's no significant impact, then increase the chunk size to 100/150/200.
[x] Ensure that the EventLogging instrumentation **is disabled** for the chunk.
[] The Ops and Services teams are notified after each deploy.
[] We pause for a day (at least) between deploys so that each team has a chance to observe the effect of increased load.
== Current status
The first 50 wikis (in alphabetical order) from the list were deployed to on Thursday, 3rd August ๐๐๐