要查看PostgreSQL的运行状态,您可以使用以下命令:
```
sudo systemctl status postgresql
```
这将显示PostgreSQL服务的当前状态,包括是否正在运行以及最近的活动。如果PostgreSQL正在运行,则输出应该类似于以下内容:
```
● postgresql.service - PostgreSQL RDBMS
Loaded: loaded (/lib/systemd/system/postgresql.service; enabled; vendor preset: enabled)
Active: active (exited) since Mon 2021-08-23 10:00:00 UTC; 5min ago
Main PID: 12345 (code=exited, status=0/SUCCESS)
Tasks: 0 (limit: 4915)
CGroup: /system.slice/postgresql.service
Aug 23 10:00:00 server systemd[1]: Starting PostgreSQL RDBMS...
Aug 23 10:00:00 server systemd[1]: Started PostgreSQL RDBMS.
```
如果PostgreSQL没有运行,则输出应该类似于以下内容:
```
● postgresql.service - PostgreSQL RDBMS
Loaded: loaded (/lib/systemd/system/postgresql.service; enabled; vendor preset: enabled)
Active: inactive (dead) since Mon 2021-08-23 09:55:00 UTC; 10min ago
Process: 12345 ExecStart=/usr/bin/pg_ctlcluster --skip-systemctl-redirect 12 main start (code=exited, status=0/SUCCESS)
Aug 23 09:55:00 server systemd[1]: Starting PostgreSQL RDBMS...
Aug 23 09:55:00 server systemd[1]: Started PostgreSQL RDBMS.
```
在这种情况下,您可以尝试使用以下命令启动PostgreSQL服务:
```
sudo systemctl start postgresql
```