今天启动我一个Rails App的时候遇到错误：
connection to server at "::1", port 5432 failed: Connection refused
Is the server running on that host and accepting TCP/IP connections?看来是psql没有运行起来，或者是被谁shutdown了，执行 postgres -D /usr/local/var/postgres 出现以下提示
2022-02-11 20:29:45.999 CST [25264] FATAL: database files are incompatible with server
2022-02-11 20:29:45.999 CST [25264] DETAIL: The data directory was initialized by PostgreSQL version 13, which is not compatible with this version 14.1.看来又是哪个地方不小心把本地的postgresql升级了，导致数据不兼容：数据库里面的数据是13版本创建的，现在psql软件版本是14，两者之间不兼容。解决办法是升级数据库中的数据格式为14版本的格式。
执行 brew postgresql-upgrade-database 对数据库中的数据进行升级。途中遇到一个问题：
There seems to be a postmaster servicing the new cluster.
Please shutdown that postmaster and try again.
Failure, exiting
Error: Upgrading postgresql data from 13 to 14 failed!
==> Removing empty postgresql initdb database...
==> Moving postgresql data back from /opt/homebrew/var/postgres.old to /opt/homebrew/var/postgres...
Error: Failure while executing; `/opt/homebrew/opt/postgresql/bin/pg_upgrade -r -b /opt/homebrew/Cellar/postgresql@13/13.5_1/bin -B /opt/homebrew/opt/postgresql/bin -d /opt/homebrew/var/postgres.old -D /opt/homebrew/var/postgres -j 8` exited with 1.执行 brew services stop postgresql，把正在运行的实例关掉，在执行 brew postgresql-upgrade-database 问题解决了。