PG::ConnectionBad: FATAL: the database system is starting up

MacでRailsアプリ開発中に、rails db:migrateをしたらPG::ConnectionBad: FATAL: the database system is starting upが出た

現象

ターミナル

$ bundle exec rails db:migrate
rails aborted!
PG::ConnectionBad: FATAL:  the database system is starting up
/Users/jun/dic/Task-twitterclone/Rblog/vendor/bundle/ruby/2.6.0/gems/pg-1.2.3/lib/pg.rb:58:in `initialize'
...

解決策

$ rm /usr/local/var/postgres/postmaster.pid         // postmaster.pidを削除
$ brew services restart postgresql         // postgresql再起動

接続確認

$ psql -l
                                    List of databases
              Name               | Owner | Encoding | Collate | Ctype | Access privileges 
---------------------------------+-------+----------+---------+-------+-------------------
 FACEBOOK_EXAM_development       | jun   | UTF8     | C       | C     | 
 FACEBOOK_EXAM_test              | jun   | UTF8     | C       | C     | 
 GraphQL-app_development         | jun   | UTF8     | C       | C     | 

OK！

参考
https://qiita.com/hirocueki2/items/327dc6e87005edf622ad
https://blog.n-z.jp/blog/2020-01-08-homebrew-postgresql.html
https://qiita.com/opiyo_taku/items/2fc4bef8a6bfd468de6a