无法连接到PostgreSQL服务器：致命：用户“postgres”的对等身份验证失败

Question

如何从 adminer 访问postgres数据库？

我更改了用户postgres的密码：

$ sudo -u postgres psql
$ postgres=# alter user postgres password 'secret';

结果：

ALTER ROLE

但我仍然在adminer上得到这个错误：

Unable to connect to PostgreSQL server: FATAL: Peer authentication failed for user "postgres"

任何想法为什么？

我有这两个用户：

postgres=# \du
                                   List of roles
 Role name |                         Attributes                         | Member of 
-----------+------------------------------------------------------------+-----------
 postgres  | Superuser, Create role, Create DB, Replication, Bypass RLS | {}
 root      | Superuser, Create role, Create DB                          | {}

但是当我使用此命令创建用户root时，我没有设置密码：

sudo -u postgres createuser --interactive

输出（为什么不要求密码？）：

Enter name of role to add: root
Shall the new role be a superuser? (y/n) y

但我仍然在adminer上得到错误：

Unable to connect to PostgreSQL server: FATAL: Peer authentication failed for user "root"

修改

这是pg_hba.conf

的一些内容

sudo nano /etc/postgresql/9.5/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
# Allow replication connections from localhost, by a user with the
# replication privilege.
#local   replication     postgres                                peer
#host    replication     postgres        127.0.0.1/32            md5
#host    replication     postgres        ::1/128                 md5

我将peer更改为ident：

# Database administrative login by Unix domain socket
local   all             postgres                                ident

# TYPE  DATABASE        USER            ADDRESS                 METHOD

# "local" is for Unix domain socket connections only
local   all             all                                     ident
# IPv4 local connections:
host    all             all             127.0.0.1/32            md5
# IPv6 local connections:
host    all             all             ::1/128                 md5
# Allow replication connections from localhost, by a user with the
# replication privilege.
#local   replication     postgres                                peer
#host    replication     postgres        127.0.0.1/32            md5
#host    replication     postgres        ::1/128                 md5

然后重新启动我的机器。但仍然没有运气。

Answer 1

从here获得答案：

local   all             postgres                                md5

然后重启服务：

sudo systemctl restart postgresql.service

Answer 2

看起来您正在使用“对等身份验证”，您希望使用“密码身份验证”。使用默认的pg_hba.conf，您可以通过指定主机名或“127.0.0.1”切换到密码验证。

请参阅Postgres documentation for authentication methods。