**Production Migration and Killing**
[x] Early 2019, investigate normalization of wb_terms
[] Finish not yet done read usecases T236979
[x] {T236901}
[x] {T205194}
[] (ongoing) {T236681}
[] (ongoing) {T232040}
[x] Fixes for writing
[x] {T234329}
[x] {T232393}
[x] {T234948}
[x] {T235117}
[] T237984 Fix Followups (bad row deletions)
[] Full rebuild of items and properties on beta
[] Full rebuild of items and properties on test
[] Identify holes in the items terms tables for prod as of 17:00 on the 19th December for rebuilding
[] rebuild holes in prod wikidata tables for items - Tracked as part of T219301 (the migration) ?
[] rebuild holes in prod wikidata tables for properties - Tracked as part of T219123, but already being done in T237984#5754602
[] Investigate orphan rows in the new terms tables (beta, test, prod) (TASK TBA)
[] Complete the Migration (Jan 2020) T219175
[] (ongoing) {T219301}
[x] Write Both
[] (Jan 2020) - Read from new schema in production
[] (Jan 2020) - Stop writing to old schema in production
[] (ongoing) {T219123}
[x] Write Both
[] (Jan/Feb 2020) - Read from new schema in production
[] (Jan/Feb 2020) - Stop writing to old schema in production
//The final steps//
[] 2020 - {T219144}
[] 2020 - Drop the wb_terms table in production
**Followups:**
[] TBD Turn on or fix the CirrusSearch Sanitizer job {T239931}
[] More and better docs for the code {T225857}
[] Refactor DatabaseTermIdsCleaner to make it easier to reason with (TASK TBA)
**Tickets that can be closed once the table is dead**
* Any open tickets on this board: https://phabricator.wikimedia.org/tag/wikidata-ugly-cat-trailblaze_wb_terms_trail_blazing/
* {T86530} - Follows the same sort of idea as this ticket, but has lots of cruft surrounding it, so bets to leave it where it is rather than pull it into a subtask of this task.
* {T197161} - Part of old trail blaze investigation
* {T205194}
* {T198868}
* {T199833}
* {T198866}
* {T142691} - This will technically not be an issue, as we won't be using wb_terms, but this could re surface with the new schema
* {T197076}
**Potentially clossable?**
* {T194144}
* {T151789}