对于Windows安装，将创建Windows用户。“psql”使用该用户连接到端口。如果您更改了PostgreSQL用户的密码，它不会更改Windows用户的密码。 只有当您可以访问命令行时，下面的命令行才能工作。

相反，您可以使用Windows GUI应用程序“c:\Windows\system32\lusrmgr.exe”。这个应用程序管理由Windows创建的用户。现在可以修改密码了。

注意:在Linux上，您可以简单地运行sudo su - postgres来成为postgres用户，然后使用psql更改所需的内容。

Find the file pg_hba.conf. It may be located, for example, in /etc/postgresql-9.1/pg_hba.conf. cd /etc/postgresql-9.1/ Back it up cp pg_hba.conf pg_hba.conf-backup Place the following line (as either the first uncommented line, or as the only one): For all occurrence of below (local and host) , except replication section if you don't have any it has to be changed as follow ,no MD5 or Peer authentication should be present. local all all trust Restart your PostgreSQL server (e.g., on Linux:) sudo /etc/init.d/postgresql restart If the service (daemon) doesn't start reporting in log file: local connections are not supported by this build you should change local all all trust to host all all 127.0.0.1/32 trust You can now connect as any user. Connect as the superuser postgres (note, the superuser name may be different in your installation. In some systems it is called pgsql, for example.) psql -U postgres or psql -h 127.0.0.1 -U postgres (note that with the first command you will not always be connected with local host) Reset the password ('replace my_user_name with postgres since you are resetting the postgres user) ALTER USER my_user_name with password 'my_secure_password'; Restore the old pg_hba.conf file as it is very dangerous to keep around cp pg_hba.conf-backup pg_hba.conf Restart the server, in order to run with the safe pg_hba.conf file sudo /etc/init.d/postgresql restart

关于pg_hba文件的进一步阅读:19.1。pg_hba.conf文件(正式文档)

当从命令行连接到PostgreSQL时，不要忘记添加-h localhost作为命令行参数。如果不是，PostgreSQL将尝试使用PEER认证模式进行连接。

下面显示了密码重置、使用PEER身份验证登录失败和使用TCP连接登录成功。

# sudo -u postgres psql

could not change directory to "/root"
psql (9.1.11)
Type "help" for help.

postgres=# \password
Enter new password:
Enter it again:
postgres=# \q

失败:

# psql -U postgres -W

Password for user postgres:
psql: FATAL:  Peer authentication failed for user "postgres"

使用-h localhost:

# psql -U postgres -W  -h localhost

Password for user postgres:
psql (9.1.11)
SSL connection (cipher: DHE-RSA-AES256-SHA, bits: 256)
Type "help" for help.

postgres=#

Edit the file /etc/postgresql/<version>/main/pg_hba.conf and find the following line: local all postgres md5 Edit the line and change md5 at the end to trust and save the file Reload the postgresql service sudo service postgresql reload This will load the configuration files. Now you can modify the postgres user by logging into the psql shell psql -U postgres Update the postgres user's password alter user postgres with password 'secure-passwd-here'; Edit the file /etc/postgresql/<version>/main/pg_hba.conf and change trust back to md5 and save the file Reload the postgresql service sudo service postgresql reload Verify that the password change is working psql -U postgres -W

如果你在macOS上运行PostgreSQL，试试这些:

Edit the pg_hba.conf file sudo vi /Library/PostgreSQL/9.2/data/pg_hba.conf Change the "md5" method for all users to "trust" near the bottom of the file Find the name of the service ls /Library/LaunchDaemons Look for postgresql Stop the postgresql service sudo launchctl stop com.edb.launchd.postgresql-9.2 Start the postgresql service sudo launchctl start com.edb.launchd.postgresql-9.2 Start a psql session as postgres psql -U postgres (shouldn't ask for password because of 'trust' setting) Reset password in the psql session by typing: ALTER USER postgres with password 'secure-new-password'; \q Enter Edit the pg_hba.conf file Switch it back to 'md5' Restart services again