psql: 致命错误: 对用户"user1"的对等认证失败

操作系统：Debian8

登录pg时可能会有提示错误：

$ psql -U user1 -d exampledb
psql: 致命错误: 对用户"user1"的对等认证失败

打开以下文件，

$ sudo vi /etc/postgresql/9.4/main/pg_hba.conf

# TYPE DATABASE USER ADDRESS METHOD

# "local" is for Unix domain socket connections only
local all all peer
# IPv4 local connections:
host all all 127.0.0.1/32 md5
# IPv6 local connections:
host all all ::1/128 md5

将 peer 改为md5：

# TYPE DATABASE USER ADDRESS METHOD

# "local" is for Unix domain socket connections only
local all all md5
# IPv4 local connections:
host all all 127.0.0.1/32 md5
# IPv6 local connections:
host all all ::1/128 md5

然后重启服务：

$ sudo service postgresql restart

再登录即可：

$ psql -U user1 -d exampledb

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