从19.10升级到20.04-错误:2http://apt.postgresql.org/pub/repos/apteoan pgdg

我在Ubuntu 19.10上,试图将其升级到20.04.1 LTS。但我在运行时发现以下错误 sudo apt update :

Hit:1 https://dl.yarnpkg.com/debian stable InRelease
Hit:2 http://apt.postgresql.org/pub/repos/apt eoan-pgdg InRelease                                           
Err:2 http://apt.postgresql.org/pub/repos/apt eoan-pgdg InRelease             
  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 7FCC7D46ACCC4CF8
Ign:3 https://download.rethinkdb.com/apt eoan InRelease 
Err:4 https://download.rethinkdb.com/apt eoan Release   
  404  Not Found [IP: 167.172.11.96 443]
Reading package lists... Done
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://apt.postgresql.org/pub/repos/apt eoan-pgdg InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 7FCC7D46ACCC4CF8
E: The repository 'https://download.rethinkdb.com/apt eoan Release' no longer has a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

有什么办法可以消除这些错误吗?

我之前没有安装postresql,也不知道为什么它会出现在错误中。