When it's possible to backfill data into the new structure, we should do so at least until the beginning of our baseline window. Let's say 2021-01-01. If backfilling is impossible, maybe we should archive the old data so that we don't destroy baseline data.
Any of these steps may be broken out into a subtask, when it makes coordination easier.
* Dependencies: wait to migrate until after these patches are deployed:
** Wait for full deployment of 1.36.0-wmf.29, which includes edit count aggregation for TemplateData.
** [[ https://gerrit.wikimedia.org/r/c/analytics/reportupdater-queries/+/657362 | Added editor type preferences ]]
** [[ https://gerrit.wikimedia.org/r/c/analytics/reportupdater-queries/+/659291 | Fix case of metric path ]]
** [[ https://gerrit.wikimedia.org/r/c/analytics/reportupdater-queries/+/656210 | Segment CodeMirror metrics by user edit count ]]
* Perform migration outside of reportupdater cronjob windows, or disable the affected jobs.
* Rename metric paths:** [[ https://gerrit.wikimedia.org/r/c/analytics/reportupdater-queries/+/661108 | Compensate for sampling ]]
** `Mediawiki.CodeMirror.preferences.byPreference.wikitext_2010_and_CodeMirror.byEnabled.true` -> `MediaWiki.CodeMirror.preferences.byPreference.wikitext_2010_and_CodeMirror.byEnabled.true`
** `Mediawiki.CodeMirror.preferences.byPreference.wikitext_2017_and_CodeMirror.byEnabled.true` -> `MediaWiki.CodeMirror.preferences.byPreference.wikitext_2017_and_CodeMirror.byEnabled.true` Perform migration outside of reportupdater cronjob windows, or disable the affected jobs.
* Purge reportupdater output directories
** `codemirror/users_codemirror_and_wikitext_2017`
** `codemirror/users_extension_codeeditor`
** `codemirror/users_gadget_wiked`
* Purge from Graphite//**—deployment TBD, must first compare with new metrics**//
** If we decide we need any of these for longer-term comparison, we can rename to e.g. start with `archive.`- .
** Most of these are deprecated because we now include aggregation `byEditCount`, don'tbe careful not to purge any paths which include this new dimension.
** `MediaWiki[wW]iki.CodeMirror.preferences.byPreference.*.byEnabled.*.byWiki.*`
** `MediaWiki.CodeMirror.sessions.byEditor.*.byEnabled.*.byWiki.*`
** `MediaWiki.CodeMirror.toggles.byEditor.*byEnabled.*.byWiki.*`
* Backfill metrics
** Delete reportupdater cached outputs and adjust start_date to cause backfill.
** TemplateWizard `user_edit_count` becomes available Jan 15th.
** TBD list other affected metrics** VisualEditor `template_dialog_*` metrics should be backfilled from Jan 1st.
* No action required
** TemplateData metric edit count buckets will switch from a custom style to common style. This is fine, we see the group labels switch for graphs spanning the deployment date.
** TemplateWizard jobs were not deployed yet, so there are no metrics to migrate.
TBD: list remaining deprecated metrics.