重新启动MacBook Pro后，我无法启动数据库服务器:
could not connect to server: No such file or directory
Is the server running locally and accepting
connections on Unix domain socket "/tmp/.s.PGSQL.5432"?
我检查了日志，下面的行出现了一遍又一遍:
FATAL: database files are incompatible with server
DETAIL: The data directory was initialized by PostgreSQL version 9.2, which is not compatible with this version 9.0.4.
9.0.4是mac上预装的版本。4]是我通过Homebrew安装的版本。
如前所述，这在重新启动之前是可以工作的，因此它实际上不可能是编译问题。我还重新运行了initdb /usr/local/var/postgres -E utf8，文件仍然存在。
类似于这些答案(1,2)，我的Postgres数据库文件在升级到postgresql 13.3后与我的Postgres版本不兼容。
不幸的是，升级Postgres数据目录失败了。
$ brew postgresql-upgrade-database
...
Setting next OID for new cluster
*failure*
Consult the last few lines of "pg_upgrade_utility.log" for
the probable cause of the failure.
Failure, exiting
Error: Upgrading postgresql data from 12 to 13 failed!
==> Removing empty postgresql initdb database...
==> Moving postgresql data back from /usr/local/var/postgres.old to /usr/local/var/postgres...
Error: Failure while executing; `/usr/local/opt/postgresql/bin/pg_upgrade -r -b /usr/local/Cellar/postgresql@12/12.7/bin -B /usr/local/opt/postgresql/bin -d /usr/local/var/postgres.old -D /usr/local/var/postgres -j 8` exited with 1.
我的解决办法是重新安装postgresql 12.7。
$ brew reinstall postgresql@12
$ brew services start postgresql@12
如果你想保留之前的postgres版本，使用brew开关:
$ 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
否则，考虑使用此brew命令迁移现有数据:brew postgresql-upgrade-database。查看源代码。
