Problem/Motivation
From #3081144: [PP-1] Database primary keys can exceed maximum integer storeable (has actually occurred, in watchdog) becomes it clear that there is a bug with a PostgreSQL backend for changing a regular serial field, that functions as the primary key, to one that is a big serial field.
Proposed resolution
Add testing for changing a regular serial field to one that uses a bit regular field and add a fix for database driver for PostgreSQL.
Remaining tasks
Write patch.
Review patch.
Commit patch.
User interface changes
None
API changes
None
Data model changes
None
Release notes snippet
TBD