PoC: Vertical split for users.incoming_email_token - step 2
requested to merge ka/spikes/430906-vertical-split-incoming_email_token-step-2 into ka/spikes/430906-vertical-split-incoming_email_token
DO NOT MERGE
What does this MR do and why?
This is PoC example MR on how to do a vertical split for a database table - extract column(s) and index(es) to a new table.
This is step 2 from the process, that does the following:
- Finalizes the back-fill of the new
user_incoming_email_settingstable
See #430906 (closed) for more details.