== Background
We will be performing an A/B test on enwiki and dewiki to gauge the performance of the page previews feature, especially in relation to fundraising.
Note that we're removing EventLogging instrumentation sampling from Page Previews in {T172291} so it's hard to guess at an ideal bucket size from previous sampling rates.
== Acceptance Criteria
[x] Launch A/B test (launched on 2:23 PM 28th August 2017)
[] Verify bucketing is working (is popupEnabled disabled for 50% of pageLoaded events?)
[x] Notify DBA and Analytics Engineering when launching, per T172322#3533459
[] and keep monitoring [[https://grafana.wikimedia.org/dashboard/file/server-board.json?var-server=dbstore1002&refresh=1m&orgId=1&panelId=17&fullscreen |EL disk usage]] ourselves)
[x] Update the [[https://meta.wikimedia.org/wiki/Schema_talk:Popups | schema talk page]] to document the new bucketing/sampling regime.
== Notes
1. Launching the A/B test requires the following configuration:
```lang=php,name=InitialiseSettings.php
/* ... */
'wmgUsePopups' => [
'enwiki' => true,
'dewiki' => true,
],
'wmgPopupsUseBetaFeature' => [
'enwiki' => false,
'dewiki' => false,
],
'wgPopupsAnonsExperimentalGroupSize' => [
// Read: Enable previews for all anonymous users by default, which is the current behaviour on all wikis except enwiki and dewiki per T162672.
'default' => 0,
'enwiki' => 0.006,
'dewik' => 0.016,
],
'wgPopupsEventLogging' => [
'default' => false,
'enwiki' => true,
'dewiki' => true,
],
/* ... */
```
~~2. Remove the `'wgPopupsAnonsEnabledSamplingRate'` and the `'wgPopupsSchemaSamplingRate'` entries from InitialiseSettings.php.~~
@phuedx: Base your work on {313a2e189f10d59166d7ed9b996bd44a11f411e7} as @Niedzielski has already done this!
== Questions
[x] What are the bucket sizes for each group per project?
@phuedx:
| wiki | on:off:control | `$wgPopupsAnonsExperimentalGroupSize` |
| -- | -- | -- |
| enwiki | 0.003:0.003:0.994 | 0.006 |
| dewiki | 0.008:0.008:0.984 | 0.016 |
With the caveat that these numbers are based on peak rates rather than average rates.
[x] What's the maximum rate of events that we can send?
@Tbayer: Depends on the overall amount of data generated in combination with current disk space concerns, see {T172322}