Jump to navigation Jump to search
Sampling method and rate
(see also phab:T157307#3282646)
- On English Wikipedia, users are bucketed randomly per session into one of two groups: feature enabled (90%) or disabled (10%). All other wikis are enabled 100%.
- A new value for userSessionToken is generated for each new user session on the first page load (and remains the same during that session). If a user has a browser that has exhausted the storage allotment for the site, it is possible their session token will change on subsequent page views.
- Users are bucketed by userSessionToken and their bucketing should persist for that session unless there is problems with storing data (see above).
- For each new session, we decide randomly whether to record events during that session (1% probability) or not (99%). Like bucketing (see above), this sampling should happen by userSessionToken and persist for that session. See $wgRelatedArticlesLoggingBucketSize in https://github.com/wikimedia/operations-mediawiki-config/blob/master/wmf-config/CommonSettings.php. See however phab:T167236.