Postgres - FATAL: database files are incompatible with server

Question

After restarting my MacBook Pro I am unable to start the database server:

could not connect to server: No such file or directory
Is the server running local         


        

Answer 1

If you want to keep the previous version of postgres, use brew switch:

$ brew info postgresql

postgresql: stable 10.5 (bottled), HEAD
Object-relational database system
https://www.postgresql.org/
Conflicts with:
  postgres-xc (because postgresql and postgres-xc install the same binaries.)
/usr/local/Cellar/postgresql/9.6.3 (3,259 files, 36.6MB)
  Poured from bottle on 2017-07-09 at 22:15:41
/usr/local/Cellar/postgresql/10.5 (1,705 files, 20.8MB) *
  Poured from bottle on 2018-11-04 at 15:13:13

$ brew switch postgresql 9.6.3
$ brew services stop postgresql
$ brew services start postgresql

Otherwise, consider this brew command to migrate existing data: brew postgresql-upgrade-database. Check out the source code.