T85414#4597677 details the current differences between the Wikibase DB schema as written in code and deployed to the WMF.
wb_terms_search_key is only in prod
term_search_key is created on install
term_search_key includes term_language, however wb_terms_search_key does not.
We need to
- rename the term_search_key index to match the wb_term_search_key used in production
- remove the usage of term_language by the index
**Priority & Impact**
Having differing schema between WMF production and what we use elsewhere and in development causes outages like the tmp1 outage.
The tmp1 index caused a massive outage, we want to avoid doing that in the future.
This task is small and should be easy to complete so lets get it done and avoid it sitting here for a year, at which point we may have forgotten about the hardships that it caused.
 Wikibase users upgrading from a version prior to this patch will have the index adjusted
 Wikibase users installing a fresh install will have the correct index
 The index should appear exactly as it does in WMF production