Postgresql：用户“ postgres”的密码身份验证失败 - Postgresql: password authentication failed for user “postgres”

问题：

I have installed PostgreSQL 8.4, Postgres client and Pgadmin 3. Authentication failed for user "postgres" for both console client and Pgadmin.我已经安装了PostgreSQL 8.4，Postgres客户端和Pgadmin3。对于控制台客户端和Pgadmin的用户“ postgres”，身份验证失败。 I have typed user as "postgres" and password "postgres", because it worked before.我已经输入了用户“ postgres”和密码“ postgres”，因为它以前可以工作。 But now authentication is failed.但是现在身份验证失败。 I did it before a couple of times without this problem.我之前几次都没​​有出现此问题。 What should I do?我该怎么办？ And what happens?那会发生什么呢？

psql -U postgres -h localhost -W
Password for user postgres: 
psql: FATAL:  password authentication failed for user "postgres"
FATAL:  password authentication failed for user "postgres"

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解决方案：

参考一： https://stackoom.com/question/WI4Q
参考二： Postgresql: password authentication failed for user “postgres”